VAM BULLETIN
An LGC publication in support of the National Measurement System
MCERTS
Ultrafine combustion particles
Clinical molecular genetic testing
The registration of forensic practitioners
Scientists in the law courts
Issue Nº 24
Spring 2001
C O N T E N T S
Keith Marshall
Editor
Contents
General enquiries about VAM to:
VAM Helpdesk
020 8943 7393
vam@lgc.co.uk
http://www.vam.org.uk
Guest column
LGC’s address:
LGC, Queens Road
TEDDINGTON
Middlesex TW11 0LY
Contributed articles
MCERTS – Setting the standards for regulatory monitoring ...........................................3
Ultrafine particles from combustion sources ...................................................................6
Clinical molecular genetic testing – A total quality approach .........................................10
ISSN 0957-1914
Focus on forensic analysis
The DTI
VAM programme:
The DTI’s programme on Valid
Analytical Measurement (VAM) is an
integral part of the UK National
Measurement System. The VAM
programme aims to help analytical
laboratories demonstrate the validity of
their data and to facilitate mutual
recognition of the results of analytical
measurements.
The VAM programme sets out the
following six principles of good analytical
practice, backed up by technical support
and management guidance, to enable
laboratories to deliver reliable results
consistently and thereby improve
performance.
1. Analytical measurements should be
made to satisfy an agreed requirement.
2. Analytical measurements should be
made using methods and equipment,
which have been tested to ensure they
are fit for their purpose.
3. Staff making analytical measurements
should be both qualified and competent
to undertake the task.
4. There should be a regular independent
assessment of the technical performance
of a laboratory.
Standards in evidence – The registration of forensic practitioners ..................................13
“We may have to go to court with this one…” ..............................................................16
Case study
The development of an industry-based PT scheme
and the benefits of participation ...................................................................................19
VAM in education
Taking the VAM message from school to the workplace................................................23
VAM news
Notes on applying ILAC Guidelines to microbiological PT schemes now available.........24
VAM products news
Computer-based training package introduces market’s first
measurement uncertainty module ................................................................................24
Buying analytical services.............................................................................................25
International news
IMEP®: Bringing SI-traceable values to field laboratories ..............................................26
LGC hosts a week of international meetings .................................................................27
Reference materials update
New reference materials now available .........................................................................28
5. Analytical measurements made in one
location should be consistent with those
elsewhere.
Chemical nomenclature
6. Organisations making analytical
measurements should have well defined
quality control and quality assurance
procedures.
Forthcoming events........................................................................................................30
A trivial system for pharmaceutical products.................................................................29
Contact points ................................................................................................................32
Cover photograph by Andrew Brookes
2
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B U L L E T I N
G U E S T
C O L U M N
MCERTS – Setting the standards
for regulatory monitoring
John Tipping
Environment
Agency
John Tipping of the Environment Agency’s
National Compliance Assessment Service
gives an overview of the Agency’s
Monitoring Certification Scheme and its
growing role in setting the standards for
regulatory monitoring.
Introduction
CERTS is the Environment Agency’s
Monitoring Certification Scheme
for instruments and monitoring services.
The scheme is built on proven international
standards to ensure that the quality
of monitoring data is high. MCERTS
consists of a product certification scheme,
accredited under the EN 45000 series
of European Standards, to deliver
certification of instruments and monitoring
services to a growing family of Agency
performance standards.
MCERTS promotes public confidence
in monitoring data, and provides industry
with a framework for choosing monitoring
systems and services that meet the Agency’s
performance specifications.
M
Background
The Agency is moving towards increased
reliance on self-monitoring by operators and
on the use of continuous monitoring and
sampling systems. This policy is well
established for processes regulated under
Integrated Pollution Control (IPC) but is
now being extended into other regulatory
regimes e.g. Integrated Pollution Prevention
and Control (IPPC), Urban Wastewater
Treatment Directive (UWWTD).
The Agency needs to have confidence in
the quality of operator monitoring, which is
where MCERTS comes in. When operators
demonstrate that their provisions for
monitoring have been tested and certified to
MCERTS standards, the Agency and the
public can have greater confidence in the
quality of the resulting data.
MCERTS was developed to address:
• the need identified by the Agency, for a
product certification scheme to help
industry select suitable monitoring
systems, and to promote public
confidence in operator monitoring data;
• the desire for UK manufacturing companies
to have independent, authoritative
endorsement of their products, which
would facilitate their access to international
markets and increase take-up of their
products in the UK.
Benefits of the scheme
The benefits of MCERTS are that it:
• is a certification scheme that is accepted
and formally recognised within the UK
and internationally;
• provides assurance to regulatory
authorities that monitoring equipment
and services approved to MCERTS
standards are fit for purpose and capable
of producing results of the required
quality and reliability;
• gives users of the monitoring equipment
or services confidence that they are
robust and conform to the Agency’s
performance standards;
• supports the delivery of accurate and
reliable data to the public;
• provides the framework for certifying
further types of monitoring instrumentation and other aspects of
compliance monitoring.
Scope of the scheme
The initial focus of MCERTS was on
continuous emissions monitoring systems
(CEMs) for chimneystacks. The performance standards for CEMs cover:
• extractive stack emission-monitoring
instruments, where a sample of gas is drawn
from the stack, generally through a sample
conditioning line, into the measuring cell;
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•
cross-stack or in-situ emission monitoring
instruments, where measurements of the
target species are made within the
gaseous atmosphere of the stack or duct.
The determinands include sulfur dioxide
(SO2), oxides of nitrogen (NO and/or NO2),
carbon monoxide (CO), carbon dioxide
(CO 2), hydrogen chloride (HCl), volatile
organic compounds (expressed as total
organic carbon (TOCs.), oxygen (O2), water
vapour (H 2 O) and particulate material
(dust). Instruments monitoring temperature,
pressure and mass flow of the stack gas, are
also included.
The measurement ranges covered for
each of the determinands depends on the
specific, industrial process application for
the CEM. The instrument supplier and
certification body agree this scope before the
system is evaluated.
In December 2000 the Agency launched
MCERTS for continuous ambient airquality monitoring systems (CAMs). The
performance standards for CAMs cover
systems that:
• continuously monitor ambient pollutant
concentrations in-situ and automatically
produce results;
• sample ambient air over an extended
period (e.g. days or weeks) onto a filter
for off-line analysis, e.g. for particulates,
metals, or PAHs.
G U E S T
C O L U M N
The determinands covered include sulfur
dioxide (SO 2), nitrogen monoxide (NO),
nitrogen dioxide (NO2), carbon monoxide
(CO), ozone (O3), particulate matter (PM10 and
PM2.5), lead, other metals (cadmium, arsenic,
nickel, and mercury), benzene, and poly-aromatic
hydrocarbons (PAHs). CAMs certified under
MCERTS will meet the performance
requirements of the Air Quality Directive and
Daughter Directives and the forthcoming
CEN standards for monitoring ambient air.
The Agency is progressively expanding
MCERTS to cover all regulatory monitoring
activities. Future developments include:
• manual stack emissions monitoring;
• portable instruments for stack-emissions
monitoring;
• data acquisition and handling;
• sampling equipment and instruments for
water monitoring;
• operators’ on-site arrangements;
•
contaminated land analysis.
(See Future Developments)
Currently MCERTS is a voluntary
scheme. However, having good quality
monitoring data is such a key element of
regulation that the Agency is considering
making MCERTS mandatory in the future
for processes it regulates.
In addition, the Agency is currently taking
part in discussions with other EU countries and
within CEN on the harmonisation of certification
requirements across Europe. The aim of these
discussions is to ensure that the requirements
for certification in Europe are equivalent and
avoid duplication of testing. In the medium
term this could result in the development of
a Europe-wide certification scheme.
MCERTS
performance standards
The MCERTS performance standards
are drawn from relevant CEN (European
Committee for Standardization) and ISO
(International Organization for Standardization) standards, where available. Prior to
publication the Agency carries out extensive
consultations on the proposed standards to
ensure they are appropriate for the intended
application. Once published, the Agency
reviews the standards on a regular basis to
keep them up to date.
For CEMs and CAMs, the standards
include:
• linearity;
• cross-sensitivity to interfering substances;
• sample pressure and temperature;
• delay time, response time;
• lower detection limit;
• repeatability;
• environmental conditions;
• susceptibility to physical disturbance;
• evaluation of the accuracy;
• reproducibility;
• availability and maintenance interval;
• long term zero and span drifts.
Testing is organised in two parts:
• laboratory based tests to ensure that
instruments perform to the required
specifications;
• field trials over a three-month period, to
ensure that the instruments are robust
and continue to work in real applications.
The structure of the scheme
MCERTS consists of two main
components; the MCERTS performance
standards as discussed above, and secondly,
and very importantly, a formally accredited
product certification scheme, the ‘delivery
vehicle’, operating under the requirements of
the EN 45000 series of European standards.
The Agency has appointed Sira
Certification Service (SCS) as the
certification body to operate the MCERTS
scheme. SCS is independent of all the
interested groups, including the instrument
manufacturers and end users. The
MCERTS scheme currently provides
product certification to EN 45011 and is
accredited by UKAS. Over the next 12
months it will be expanded to include
personnel certification to EN 45013. There
will also be a register of MCERTS
equipment and services.
The National Physical Laboratory and
AEA Technology currently carry out
laboratory and field testing. The Agency is
also publishing test-house performance
standards so that other organisations can
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offer testing services to MCERTS standards.
All testing must be accredited to ISO/IEC
17025, the international standard for general
operating criteria for testing laboratories,
and meet the MCERTS standards.
The evaluation of results obtained
during the laboratory and field-testing is
carried out by the scheme, using a group of
independent, qualified people known as the
Certification Committee.
The importance of
product certification
Product certification under MCERTS
requires an instrument manufacturer to
demonstrate that the manufacturing process
is controlled under a quality management
system and produces instruments that
deliver consistent performance. Once an
instrument is certified the manufacturer has
to inform the certification body running the
Scheme of any planned design or
manufacturing changes to the instrument
that affect performance. The certification
body then assesses the proposed changes,
and carries out further tests if required, to
ensure a modified instrument still meets the
MCERTS performance standards. As a
further check, the certification body also
audits manufacturers each year.
Design and manufacturing changes take
place quite frequently in monitoring
equipment. Product certification is critically
important to track any changes and provide
assurance to potential customers and regulators
that instruments manufactured months or
maybe years after the original instrument was
certified, still meet the MCERTS standards. As
an additional safeguard, the MCERTS
certificate has a lifetime of five years, after which
an instrument has to be resubmitted for more
detailed assessment and re-testing (if required).
Financing of the scheme
MCERTS is self-financing with costs
recovered from fees charged to applicants to
the scheme. The fees cover:
• the application for instrument certification;
• laboratory and field tests;
• preparation of test reports;
• assessments by the Certification Committee;
• preparation of the MCERTS certificate;
• promotion and policing of the Scheme;
• the costs of sustaining accreditation to
EN 45011.
G U E S T
Instrument certification
procedure
The MCERTS certification procedure
has been designed to be as simple and
straightforward as possible. It consists of the
following stages:
Initial application
The supplier of the equipment or service
submits an application to SCS, together with
a clear identification of instruments
submitted, including two sets of drawings, a
copy of any relevant control software, and
evidence of quality control procedures, e.g.
ISO 9001.
Selection of the
Certification Committee
SCS then appoints a Certification
Committee, which normally consists of three
experts in the products or services under
test. The committee members must be
impartial; for example, they must not have
been involved with the specific manufacturer
or service supplier in the previous two years.
Review of application
The Certification Committee reviews the
application and agrees the relevant
performance standards and appropriate
laboratory and field tests for the intended
applications of the products or services.
Quotation for testing
SCS, in conjunction with the applicant,
asks qualified test laboratories (initially NPL
and AEA Technology) to quote. The client
confirms the test programme, test schedule,
and quotation, usually in a preliminary
meeting with SCS and the test laboratories.
The client places a contract with SCS to cover
all testing and certification, after which SCS
places contracts with the chosen laboratories.
Laboratory and test methods
The manufacturer installs and
commissions the equipment at the test
laboratories as required. After testing, the
reports are sent to SCS and the
manufacturer. The testing laboratory
immediately informs SCS of any failures
during testing, to allow the applicant to take
corrective action.
Review of test results
The Certification Committee reviews all
test results and decides to issue or refuse a
certificate. The reasons for refusal will be
reported, as well as any special conditions
applying to the certificate. The certificate and
C O L U M N
Future Developments
The Environment Agency is
expanding MCERTS progressively to
cover all regulatory monitoring activities.
Future developments include:
Manual stack emissions monitoring
The extension of MCERTS to manual
stack emissions testing will include two
performance standards; one for
organisations involved in testing, providing
sectoral guidance to supplement the
general requirements of ISO 17025, and
the second for stack testers. Stack testers
will be certified under the personal
competency standard EN 45013. The
Agency carried out a consultation on its
proposals in 1999 and received widespread
support. The work is a collaboration with
the Source Testing Association (STA), the
primary trade association for stack testing
organisations in the UK. It is hoped to
launch the Scheme in late 2001.
Portable instruments for stackemissions monitoring
Portable instruments are increasingly
being used for stack monitoring. The
MCERTS standards are being developed
in collaboration with CoGDEM, the trade
association representing instrument
manufacturers and the instrument group
of the STA. The consultation on the draft
standards will take place in early 2001.
Data acquisition and handling
Continuous monitoring systems
produce large amounts of data requiring
processing and storage. It is important that
these data are handled correctly to ensure
reports submitted to the Agency are
correct and meet the regulatory
requirements. Increasingly these
requirements are defined in EC Directives,
e.g. Large Combustion Plant Directive,
Hazardous Waste Incineration Directive.
A performance standard for data
acquisition and handling will be produced
during 2001. The Agency is in the final
stages of preparing a technical
specification prior to issuing invitations to
tender for the work.
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Sampling equipment and instruments
for water monitoring
MCERTS performance standards are
in preparation for sampling equipment and
instrument for water monitoring. These
cover automatic waste water sampling
equipment to support the Agency’s
implementation of the Urban Waste Water
Treatment Directive, and instruments
measuring flow, turbidity, ammonia, and
pH. Consultation on the draft standards is
expected to take place in spring 2001.
Further standards are planned for
instruments measuring chemical oxygen
demand, phosphate, dissolved oxygen,
nitrate and total organic carbon.
Operator on-site arrangements
MCERTS certified monitoring and
services can only deliver good quality
monitoring data if the operators’ on-site
arrangements are also of a high standard,
e.g. sampling is carried out at a
representative position in the stack,
instruments are calibrated correctly on
installation and annually, maintenance is
carried out properly. This standard will
address these issues and capture the
requirements of the forthcoming CEN
Standard on quality assurance of
monitoring arrangement being produced
by Working Group 9 of CEN Technical
Committee 264.
Contaminated land analysis
The Agency is moving to the risk
based regulation of contaminated land. In
support of this policy operators are already
required to submit test reports to the
Agency from analytical laboratories
accredited by UKAS to ISO 17025. The
MCERTS standard in development will
provide sectoral guidance to supplement
the general requirements of ISO 17025.
The MCERTS standard will not specify
the test methods themselves but set the
minimum performance requirements for
the test methods used by the laboratories.
A consultation on the draft standard is
planned for spring 2001.
G U E S T
C O L U M N
the accompanying drawing schedules defining
the instrument will list the valid range of
applications and processes. These can be
extended beyond the test application or
process by agreement with the Certification
Committee. An appeals procedure can be
invoked in the event of any disagreement.
Further information
For general questions about MCERTS,
please contact:
John Tipping
Environment Agency
National Compliance Assessment
Service
Cameron House
C O N T R I B U T E D
White Cross Industrial Estate
South Road
LANCASTER
LA1 4XQ, UK
Tel
+44 (0)1524 581901
Fax
+44 (0)1524 842709
Email John.Tipping@
environment-agency.gov.uk
For information on MCERTS certification,
or applications, then please contact:
Ian Knott
Sira Certification Service
South Hill
CHISLEHURST
Kent BR7 5EH, UK
Tel
+44 (0)20 8467 2636
Fax
+44 (0)20 8467 6515
Email Idknott@siratc.co.uk
General email: sales@siratc.co.uk
Further information on the certification
process can be found within the SCS
publication, ‘A Guide for Certification of
Continuous Emission Monitoring Systems
under the Environment Agency’s MCERTS
Scheme’, from the SCS web site,
http://www.sira.co.uk. Both this web
site, and the Agency’s web site,
http://www.environment-agency.gov.uk
contain more information about MCERTS,
and an up-to-date list of certified instruments.
A R T I C L E S
Ultrafine particles from combustion sources
John McAughey
& Ian Marshall
AEA Technology
ombustion has long been known as a
source of soot and sulfate-based
particulate material. As combustion sources
have become more efficient, measurements
have shown that significant numbers of submicron diameter particles may be formed.
Recent epidemiological evidence has
implicated these particles as a key factor in
cardiac and respiratory disease in susceptible
population sub-groups. Thus, there has been
a significant increase in measurement of submicron (or ultrafine particles), with respect to
combustion emissions, air quality and
toxicology. To date, most world-wide activity
has focused on vehicle emissions. This article
describes standards and calibration activities
supporting the automotive and oil industry,
and government.
C
Background
In recent years, there has been
increasing interest in the properties and
applications of nanoparticles, particularly in
the fields of materials, environmental health
and combustion emissions. Despite this
increasing interest, there is little consensus
on a size definition of nanoparticles or
ultrafine particles, with them being
described variously as < 10 nm, < 100 nm,
and sub-micron (< 1000 nm).
This article will address activities in the
fields of combustion emissions from mobile
sources, where the particles of interest are
< 100 nm diameter.
Combustion emissions
from mobile sources
It is recognised that all combustion
related activities generate particles. This is
most noticeable with open fires, which may
produce a sooty flame, but is also true for
more controlled combustion sources, where
the particles are less visible. To date most
research and measurement activity has
focussed on vehicle emissions.
The measurement of particles from
vehicle emissions is a comparatively new
field, which has originated in response to
concerns with the health effects of respirable
particles in the ambient environment.
Respirable particles are commonly referred to
as PM10, that is, particles smaller than 10 µm
aerodynamic diameter. New air quality
standards for PM10 have been promulgated
in the EU and US in response to concern
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over health effects attributed to particles,
although the US regulations have since been
contested and are under review. In the EU,
the Daughter Directive (90/30/EC) sets
targets for 2005 and 2010, but these are
subject to an on-going review process.
It is recognised that an important part of
this review process is to better define
particulate matter. Whilst all other air
quality standards are based on defined
chemical entities, particulate matter is
known to be a complex mixture with respect
to particle size and chemical composition.
Particle size is a key determinant of the
environmental behaviour, persistence and
fate of particles in the environment, and also
influences the regional deposition of
particles in the human lung. Chemical
composition is likely to influence the
potential toxicity of these particles.
However, there is a growing recognition
that other particle characteristics may have a
more significant impact on health than total
particulate mass, including particle diameter,
surface area, number concentration and
composition. It is also recognised that over
90% of the number of diesel particles reside
in the range below 100 nm while only
1–20% of the mass typically resides in the
same ultrafine particle range. The
parameters used to characterise diesel
particles need to reflect these new concerns.
C O N T R I B U T E D
Particle emissions from diesel engines
have been studied in the greatest depth and
typically comprise 3 modes:
• An accumulation mode consisting of a
complex mixture of agglomerated solid
carbonaceous material and ash; this
mode appears to be stable and
reproducible, with typical diameters in
the region of 50 – 300 nm. Solid carbon
is formed during combustion in local
fuel-rich regions. Much of the carbon is
subsequently oxidised and emitted as
solid agglomerates.
• A volatile nucleation mode comprising
sulfate and condensable organic
compounds as a particle/droplet; this
mode has a typical diameter in the
region of 5 – 30 nm, although smaller
particles have also been observed. These
particles are formed by the homogenous
nucleation of sulfate (emitted SO 2
converts to SO 3, which in turn forms
sulfate droplets). Volatile or soluble
organic compounds derived from
unburned fuel and evaporated
lubricating oil (SOF), condense upon
these seed nuclei. This mode has been
shown to be labile to heat and can be
removed by heating in the presence of a
thermal denuder. Formation of this
mode can be reproducible under
controlled conditions, but is highly
dependent on dilution ratio, dilution
rate, temperature, humidity and the
residence time prior to tail-pipe dilution.
• A coarse mode comprising aggregates of
accumulation mode particles, which are
believed to have been deposited and reentrained in the exhaust system; particle
diameters may be in the region of
1–2.5 µm. This mode tends to show poor
reproducibility under measurement and
in practice many automotive sampling
systems cut-off below this mode.
A series of typical particle size distributions
with different sample temperatures and
sample residence times from a diesel engine
is shown in Figure 1, as measured by a
Scanning Mobility Particle Sizer (SMPS),
which measures the electrical mobility
diameter. It is notable that the carbon based
accumulation mode is reproducible under
the 3 sampling conditions, with a median
diameter of 50 nm. In contrast, the sulfate
based nucleation mode increases in number
concentration as sampling temperature
A R T I C L E S
Figure 1: Particle size distributions from a diesel engine as
measured by SMPS.
decreases; and with residence time in the
system, consistent with more favourable
conditions for homogeneous nucleation of
sulfate1. In this case the median diameter is
8 – 15 nm, increasing with increasing
residence time.
Particles from spark-ignition engines are
qualitatively similar to those from diesel,
most prominently in the volatile nucleation
mode. Particles from spark-ignition engines
are less well understood, but are believed to
comprise more volatile SOF and sulfate
equivalent components. However, emission
factors are two to three orders of magnitude
lower than for diesel.
For particle size measurement, new
specialist sampling and measurement
techniques have been deployed, generally
under existing test cycles for regulated
emission measurements, where sampling is
carried out on chassis dynamometer systems
from full-flow constant volume sampling
systems. It is notable that in a review
conducted for the US Environmental
Protection Agency1, only eight laboratories
in the world were conducting such particle
size measurements on a routine basis. This
number has increased greatly in the
subsequent period, and as such, this has
been an important period to validate
sampling and measurement for both industry
and regulators.
Historically, early work on the
measurement of diesel aerosols was
conducted in the laboratory and on the
roadway2,3. More recently there have been
further review papers addressing measurement of differing aspects of the emitted
particles4. Much of the current interest in
further characterisation of particulate
emissions arose from Bagley et al 5 , who
described an increase in the formation of
ultrafine particles in a new technology
engine, where particle mass emissions were
being reduced. Recent papers have also
described low-concentration measurement
of spark-ignition engine emissions 6,7,8 and
measurement of diesels fitted with
particulate traps9,10.
The most significant issue in this field is
the nature of the nucleation mode particles
formed as a consequence of the diluting
conditions and residence time in the
measurement system1. As noted above, these
‘new’ particles are typically less than 5 – 30
nm diameter and consist of sulfate and
condensable organic material. There is an
on-going research effort to determine the
nature of these particles. This relates
principally to determining whether they are
formed in real-life roadway conditions, or
whether they exist solely as an artefact of the
existing sampling system. If these sub-10 nm
particles are observed by roadways under
ambient conditions, they must be further
assessed as to their potential health
implications. (Note: an ambient particle
mode of 20 nm has been observed at or near
roadways in a number of cities; however
there are currently no composition data
available to confirm that these are derived
directly from nuclei-mode diesel emissions).
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II
Normalised particle number concentration
Particle diameter
C O N T R I B U T E D
Health
Interest in this field is driven by concerns
that exposure to combustion emissions may
be a significant source of poor cardiorespiratory health in susceptible population
groups. A number of studies11 have variously
concluded that in the larger countries of
Western Europe, exposure to ambient
particles contributes each year to many
thousands of acute deaths from respiratory or
heart disease in the days immediately
following pollution episodes, with pro rata
effects in other countries. The associated loss
of life is strictly unknown, but believed to be
in weeks or months rather than years, on
average. There is less well-established
information about the additional effects of
longer-term exposure to ambient particles,
and these are less easily to quantify reliably.
In the UK, the Committee on
the Medical Effects of Air Pollutants
(COMEAP)12, citing Brunekreef 13, concluded
that these ‘chronic’ effects might be the
dominant ones. A summary table (Table 1)
summarises briefly the various particle metrics
(size and composition) considered with
respect to health effects, confirming the
complexity of the problem of attributing risk
from the particle mixture. It is noted however,
that the estimated health costs of increased
particle exposures with respect to mortality
and morbidity, may be equivalent to up to
1.7% of Gross Domestic Product 11. It is
within this context, that there are significant
research programmes by industry and
government seeking to modify engine and fuel
technologies and further reduce emissions.
Hence, there is a pressing requirement for
sampling and measurement standards.
Measurement
A number of techniques have been
applied to the measurement of particle size
of vehicle particle emissions. The most
commonly adopted techniques are those
which are able to conduct near real-time
measurements. These include electrical
mobility analysers such as the Scanning
Mobility Particle Sizer (SMPS: TSI Inc.,
MN – Figure 2 illustrates size fractionation
via an electrostatic classifier; subsequent
measurement is conducted by a
Condensation Particle Counter). Inertial
impaction instruments such as the Electrical
A R T I C L E S
Metric
Evidence Source
Strength of Evidence
PM Mass
Epidemiology
Consistent association between PMx
and reported health effects – a useful
unifying PM measure
PM Particle Size
Epidemiology
Dosimetry
Toxicology
Indications from epidemiology and
toxicology that fine PM2.5 is more
potent than coarse PM on a mass
concentration basis (although ambient
composition will vary). Finer particles
penetrate more readily into lungs, cells
and through tissue barriers
PM Surface Area
Toxicology
Finer particles have greater surface
area per unit of mass; Oberdorster data
implies toxicity for a known material is
consistent with available surface area
Ultrafine PM
Epidemiology
Dosimetry
Toxicology
Growing recent epidemiological
database suggesting that this fraction
may be of importance.
Toxicology – inflammatory reponse on
ultrafine exposure
Particle number concentration is also
a metric of interest
Metals & Compounds
Toxicology
Have cytotoxic and inflammatory
properties. The “metals hypothesis”
associated with the soluble metal
fraction of ROFA and may be related
to the ability of these metals to catalyze
production of free radicals in tissues.
Limited epidemiology data from Utah
steel works studies
Acids
Toxicology
Human effects observed in laboratory
but significant neutralising capacity
in lung
Organics
Toxicology
Compound-specific effects – particular
concern for lung cancer
Sulfate / Nitrate
Toxicology
Human effects observed in laboratory;
metric is often under-reported in
ambient measurements
Peroxides
Toxicology
Plausible toxicology route but ambient
concentration low
Elemental Carbon
and Soot
Epidemiology
Toxicology
Soot has irritant, mutagenic, and
carcinogenic properties that vary with
delivered dose and the properties of
the sorbed materials. It is plausible that
it could exert both short-term (irritant)
and long-term (carcinogenic) effects.
Co-factors
(SO2, NOx, O3, CO)
Epidemiology
Significant differences in health
markers for different gaseous
co-pollutants with location
Table 1: Summary of particle metrics.
Low Pressure Impactor (ELPI : Dekati,
Finland) have also been used widely. The
SMPS instrument operates in the size
regions from 7 – 300 nm or 15 – 700 nm
and has been adopted widely for the
measurement of particle size distribution
under steady-state conditions, or to monitor
specific size ranges throughout transient
cycles. The ELPI operates from 35 – 10,000 nm
and has been used widely to measure size
distribution data during transient cycles.
Isokinetic sampling is achieved readily,
for the particle sizes of interest in the sub-10 µm
region. Sample losses have been assessed by
theory and measurement 1,14,15. Losses are
8
V A M
B U L L E T I N
principally by thermophoresis with minimal
losses by diffusion and impaction.
VAM Programme
Within the VAM Programme, a
programme of work has been conducted
aimed at providing industry with improved
tools and ‘know-how’ for the calibration for
aerosol instrumentation that measures the
number concentrations of ultrafine (<100 nm)
particles. This has comprised two parts:
• A Design Standard has been proposed
and tested successfully for calibrating the
linearity of aerosol number-based
instrumentation.
C O N T R I B U T E D
Figure 2: Electrostatic classifier for discrimination
of sub-micron particles by electrical mobility.
•
The Vehicle Particulates Emission Club
(VPEC) has been established as a
subscription-based research club, and as
a partnership between industry and
government, to conduct research with
respect to generic sampling and
measurement issues.
Number calibration standard
A programme of work has been
performed to develop a design standard for
calibrating number concentration measuring
instrumentation, for aerosol instrumentation
in the ultrafine region. Emphasis has been
on achieving a robust and cost-effective
capability that can be used both in specialist
calibration laboratories as well as being able
to be taken to the point of measurement.
The potential of using accurate dilution
(over a wide concentration range) as a
means of providing a traceable and costeffective means of calibrating the linearity of
number-measuring aerosol instrumentation
was identified as a key component of this
study. An absolute dilution performance of
better than 10% was identified as a design
target. A Sample Conditioning System
(SCS) meeting this target has been designed
and manufactured. The SCS has undergone
comprehensive calibration and validation in
terms of temperature and pressure sensor
calibration, temperature compensation of
measured pressures, flow calibration,
pressure stability, leak-tightness and dilution
verification with a CO gas standard16. An
example calibration of a TSI Condensation
Nucleus Counter was also undertaken
utilising the SCS.
Vehicle Particle Emissions Club
The Vehicle Particle Emissions Club
(VPEC) is a shared-cost research club
established in the UK in 1999, in a
collaboration of industry and Government,
with a view to assessing priorities in generic
measurement issues and establishing a
research programme to address these areas.
The founder members are shown in Table 2.
The Club has to date commissioned studies
to calibrate the Scanning Mobility Particle
Sizer with respect to size standards and the
draft number standard. In parallel, a roundrobin exercise is being conducted at a
number of chassis dynamometer facilities in
the UK, using a reference vehicle and
SMPS, versus local SMPS instruments
(http://www.bigfoot.com/~vpec). It is likely
that the remit of the Club will widen to
address other combustion sources of particles.
A R T I C L E S
and the US, with good links between all
parties. In the US, a large programme of
work has been sponsored by EPA and
conducted by University of Minnesota
(http://www.me.umn.edu/centers/cdr/Proj_E
PA.html). Most recently, the Co-ordinating
Research Council (CRC) conducted a
sampling and measurement workshop (Paris
– May, 2000) with details reported at
http://www.crcao.com.
In Europe, another intercomparison
programme has been conducted for the
SMPS instrument by a number of German
and Swiss laboratories, co-ordinated by the
Institut für Gefahrstoff-Forschung der BBG.
A further programme on particle emission
factors is being conducted within the
European Commission 5th Framework
Programme, co-ordinated by University of
Thessaloniki.
Conclusion
This is an interesting period for
measurement of ultrafine particles; the
number of measurements will increase as
legislators move to introduce new standards,
and as industry moves to improve existing
products and introduce new technologies. It
is clear that the need for improved sampling
and measurement validation has been
recognised, and that significant progress is
being made at an international level.
REFERENCES
1. Kittelson, D. B. (1999), Review of diesel
particulate matter sampling methods,
USEPA, Downloadable from WWW at
Centre for Diesel Research, University
of Minnesota.
2. Kittelson, D. B., Doan, D. F., and Verrant
International activities
As well as UK-based activities,
there are significant activities in Europe
J. A. (1979), Investigation of a diesel
exhaust aerosol, SAE Technical Paper
Series No. SAE 780109. Warrendale PA
Government
Industry
Research Organisations
Department of Trade &
Industry, UK (VAM)
Castrol, UK
AEA Technology, UK
Department of Environment,
Transport & the Regions, UK
Ford, UK
Motor Industry Research
Association (MIRA), UK
US Department of Energy,
via the National Renewable
Energy Laboratory, Co
Shell Global
Solutions, UK
Ricardo Consulting
Engineers, UK
Table 2: Founder Members of the Vehicle Particle Emissions
Club (VPEC)
9
V A M
B U L L E T I N
C O N T R I B U T E D
A R T I C L E S
3. Dolan, D. F. and D. B. Kittelson (1979),
ignition engine, SAE Technical Paper
Quantification of the Effects of Air
Roadway measurements of diesel
Series No. SAE 980528. Warrendale PA
Pollution on Health in the United
exhaust aerosols, SAE Technical Paper
Series No. SAE 790492. Warrendale PA
Kingdom. UK Department of Health.
8. Maricq, M., Chase, R. E., Podsiadlik, D.
HMSO, London
H. and Vogt, R. (1999). Vehicle Exhaust
4. Lepperhoff, G. et al. (1994), Methods to
Particle Size Distributions: A Comparison
13. Brunekreef B. (1997), Air pollution and
analyse non-regulated emissions from
of Tailpipe and Dilution Tunnel
life expectancy: is there a relation?,
diesel engines. SAE Technical Paper
Measurements, SAE Technical Paper
Occup Environ Med; 54: 781-784.
Series No. SAE 941952. Warrendale PA
series 1999-01-1461. Warrendale, PA
5. Bagley, S. T., Baumgard, K. J., Gratz, L. D.,
9. Baumgard, K. J. and Johnson, J. H.
Johnson, J. H., and Leddy, D. G. (1996),
(1992). The effect of low sulfur fuel and
Characterization
and
a ceramic particle filter on diesel
Aftertreatment Device Effects on Diesel
exhaust particle size distributions,
Emissions, Health Effects Institute
Technical Paper Series, No. 920566,
Research Report Number 76, 88 pp.
SAE: Warrendale, PA
14. Dickens, C. J., Ball, M. H. E., Booker,
of
Fuel
6. Rickeard, D. J., Bateman, J. R., Kwon,
10. Mayer, A. et al (1997). VERT- Clean
Y. K., McAughey, J. J. and Dickens, C. J.
Diesel engines for tunnel construction,
(1996),
SAE 970478, Warrendale PA
Exhaust
particulate
size
Paper 961980, Warrendale PA
Hughes, M. (1997), Evaluation of
Instruments for Vehicle Emission
Particle Sizing, AEA Technology Report
AEAT-1180, 69 pp. (Unclassified).
15. Ball, M. H. E. (1998), Measurement of
Ultrafine Particles – Guidance Notes,
AEA Technology Report AEAT-3936
(Unclassified).
distribution: vehicle and fuel influences
in light-duty vehicles, SAE Technical
D., Donald, J. R., Tope, A. M. and
11. World Health Organisation (1999),
downloadable from www.who.dk/
London99/WelcomeE.htm
16. Marshall, I. A. and Booker, D. R. (1999),
Development of an Ultrafine Number
Concentration
7. Graskow, B. R. and Kittelson, D. B.
(1998), Characterisation of exhaust
12. COMEAP (1998), Committee on the
particulate emissions from a spark-
Medical Effects of Air Pollutants,
Standard,
AEA
Technology Report No. AEAT/EEQA0028 (Unclassified).
Clinical molecular genetic testing –
A total quality approach
Rob EllesI, Simon RamsdenII, Simon PattonI, II,
Su StenhouseII, David BartonI
EMGQNI & UK NEQAS for Molecular GeneticsII
egional Genetics Centres in the NHS
have introduced molecular genetic
testing associated with inherited disease over
the last 15 years. Currently there are 24
laboratories in the UK offering a service
portfolio for the major single gene disorders.
In the early days few inherited diseases were
open to a diagnosis and the techniques such
as Southern blotting were very cumbersome
R
I
II
EMGQN: European Molecular Genetics
Quality Network
UK NEQAS: UK National External Quality
Assessment Scheme
and laborious, requiring a great deal of
technical and scientific skill to achieve
accuracy, reliability and a timely response to
clinical need. The introduction of PCRbased techniques, along with the possibility
of a diagnosis for most of the common
genetic conditions, transformed the
landscape of genetic testing. During this
period the professional groups in the UK
and elsewhere began to focus their attention
on quality issues relevant to all areas of the
analytical process.
In the last five years the recognition of
1 0
V A M
B U L L E T I N
genes pre-disposing individuals to some
common diseases (breast/ovarian and bowel
Molecular genetic testing
‘Molecular genetic testing’ is a term used
to describe many diagnostic activities
relevant to sporadic cancers and
infectious disease. However this article is
restricted to genetic testing for inherited
disease in humans with DNA as the
normal analyte.
C O N T R I B U T E D
cancer), the availability of better instrumentation – fluorescent DNA sequencers for
example – have set the pace towards a more
service-orientated approach.
The next five to ten years will see
genetic testing take its proper place in the
armoury of medicine. We can foresee an
increasing understanding of disease
processes, a need to stratify the disease
population by genotype and the use of
pharmacogenetic testing to improve clinical
management. In hardware terms the
introduction of high throughput (capillary
electrophoresis DNA sequencing) and later
parallel processing (gene chip) technologies
will mean that access to genetic testing
is less limited by cost and reporting
time constraints.
Genetic testing has a high media profile
and the consequent raised expectations by
the public place a responsibility on service
providers to retain public confidence and
introduce quality systems in line with
current clinical analytical standards.
Although genetic testing for inherited disease
is not unique in the ethical and social issues
that it presents, it does have features that
emphasise the need for high quality
standards. The establishment of a person’s
genotype is usually a ‘one off’ test and is
unlikely be repeated in their life-time.
Furthermore, the results may not only be
highly predictive of their own health status,
it may also have important implications for
the health of their immediate and extended
family. Errors in molecular genetic testing
are therefore perceived to have serious and
long-term consequences.
For these reasons a strong link has been
established between genetic testing in the
laboratory and the availability of genetic
counselling. Pre- and post- test genetic
counselling may be as important a part of
the quality of care package for the genetics
patient as an examination before the
procedure and subsequent follow-up is for a
surgical patient. Genetic testing laboratories,
working closely with clinical colleagues,
place a strong emphasis on providing full
interpretations of their data and consider
that the output from the laboratory is not
limited to the technical genotype but
includes a modified genetic risk presented to
inform the counselling process (Figure 1).1
A total quality approach must start with
the promotion of an appropriate skill and
knowledge base in the staff and attention to
their motivation and confidence in career
progression. The professional societies
representing scientists in the field have been
active since 1990 in developing training
structures. In the last few years they have
strongly supported state registration of staff,
which is designed to ensure a basic level of
competence and promote public confidence
in groups with a critical role in patient care.
The statutory register for clinical scientists
came into force in October 2000 (Table 1).
While clinical scientists involved in
genetic testing have always been aware of the
importance of quality control in their
laboratories, independent assessment of this
A R T I C L E S
Figure 1: Added value in
genetic testing.
quality first began with a trial External
Quality Assessment (EQA) scheme
organised by the Clinical Molecular
Genetics Society in 1990–91.
Within 3 years this scheme received
Department of Health funding as a pilot
programme and in 1995 it came under the
UK National External Quality Assessment
Scheme umbrella. UKNEQAS covers most
UK laboratory proficiency schemes in
clinical analysis. The molecular genetics
scheme has been accredited by Clinical
Pathology Accreditation Ltd.
The EQA scheme for molecular genetics
has introduced some advanced features in an
attempt to assess the whole analytical process,
including not only the technical aspects of
genotyping but elements of pre-test handling
and the post-analytical interpretation of
data. In brief – centres receive validated
clinical DNA samples from the UKNEQAS
for molecular genetics, forming a mock
clinical case, complete with clinical details,
patient identifiers and a request for a
REGULATORY BODY/ROLE
FUNCTION
Clinical Molecular
Genetics Society
Recruitment,
appointments
and grading
Royal College of
Pathologists
Guidance to Department
of Health on grading
Post-graduate
basic training
2-year super-numary
training in centres
accredited by the
Training Accreditation
Board
Career-grade training
Preparation programmes
for membership of the
RCPath
Possible 2/3 years
after entry to an
assessed post
Scientists not in
training are registered
for CPD
Table 1: Quality and training in the scientific work-force
1 1
V A M
Department
of Health
Guidance to Hospital
Trusts, National panel
of external assessors
Examinations leading
to Membership of the
RCPath
Statutory registration
Continued Professional
Development (CPD)
Council for Professions
Supplementary
to Medicine
B U L L E T I N
C O N T R I B U T E D
disease-specific analysis. Laboratories are
asked to genotype the sample(s) and return a
normal laboratory report including their
interpretation of the data in the light of the
clinical information supplied. Reports are
marked by expert assessors and assigned a
numerical score. This process assesses pretest handling (transcription of correct patient
identifiers) and the accuracy of the genotype
(mutation identified/no mutation detected,
marker alleles scored). In addition, assessors
look for mention of key points of
interpretation that may include the
significance of the test result in light of the
clinical details, limits of sensitivity or
specificity of the test, key recommendations to
the clinicians, implications of the results for
other family members and requirements for
further testing.
1997
Hereditary bowel cancer
1998
Huntington’s disease
1999
Fascio Scapulo
Humeral Dystrophy
2000
Familial breast/ovarian cancer
Spinal Muscular Atrophy
Friedreich’s ataxia
Meeting for EQA scheme
organisers and assessors
Charcot Marie tooth disease
Y-chromosome microdeletions
2001
Internal Quality Control
Meeting for EQA scheme
organisers and assessors
Retinoblastoma
Fragile X disease
Prader Willi syndrome/
Angelman syndrome
Table 2: European best
practice meetings held or
planned 1997–2001
Studies showing variation in the
performance of laboratories across Europe,
as well as the demand from European centres
to be included in the UKNEQAS, led to a
successful bid to the European Union’s
Standards, Measurement and Testing
Programme for a pilot Quality Network.2, 3.
This European Molecular Genetics Network
(EMQN) of 18 partners is funded until the
end of 2001, to evaluate disease-specific
EQA schemes being offered to approximately
350 centres, from six European EQA scheme
providers. To date nearly 400 European
centres have participated in schemes
A R T I C L E S
promoted or associated with EMQN most of
which are closely modelled on the
UKNEQAS system (Table 3).4
An emphasis on the interpretation of
data inevitably introduces a subjective
element to a Laboratory Proficiency
Scheme. Early in the development of the
UKNEQAS system, this led to a recognition
of a need to develop a consensus amongst
the laboratory community on what
constituted ‘best practice’. The other main
driver for action was the recognition, in
looking at EQA returns, of a great
divergence in methodologies and practice
(for instance, in a single disease test, up to
ten different genetic markers might be in use
in different centres). Bringing scientists
together to discuss best practice not only
resulted in a convergence of methodologies
(without necessarily imposing rigidity in a
fast moving area of technology), but also in
agreement on guidelines that could inform
both the participants in EQA schemes and
the expert assessors, who mark the returns
from the laboratories. Guidelines were first
published by the CMGS (www.cmgs.org)
and included advice specific to a disease
diagnosis and also elements of internal
quality control, for instance handling data
and samples in the laboratory and good
reporting practice.
Subsequently the EMQN was funded to
continue this process at European level and
has taken on board publishing the resulting
guidelines through its web site
(www.emqn.org). Fourteen best practice
meetings will be held over three years. The
link with EQA gives guidelines an authority
(laboratories need to follow the guidelines to
perform well in EQA) whilst the consensus
mechanism from which guidelines are
produced prevents them from assuming an
authoritarian or arbitrary character.
A key element of standardised testing
systems is the availability of Certified Reference
Materials (CRMs) that are traceable, stable
and exhibit known variance. Molecular
genetics, in common with other analytical
disciplines, requires reference materials5. These
would consist of materials with a known
genotype (mutation or variant carrier), or
‘wild type’ (free of pathogenic variants).
Reference materials of this sort are entirely
lacking or poorly controlled in this area and
the stability and variability parameters have
not been explored at all. In response to an
1 2
V A M
B U L L E T I N
UKNEQAS EMQN
Cystic Fibrosis
✓
✓*
Duchenne Muscular
Dystrophy
✓
✓
Huntington’s disease
✓
✓
✓
✓
✓
✓
Prader Willi/
Angelman’s syndrome
✓
✓
Familial Breast/
Ovarian cancer
Freidriech’s ataxia
Y-chromosome
micro-deletion
Charcot Marie
Tooth Disease
Fragile X disease
✓**
✓
✓
Retinoblastoma
Mitochondrial dseases
Spinal Muscular Atrophy
Spino Cerebellar Ataxiss
Myotonic Dystrophy
✓
✓
✓
✓
✓
✓
✓
* in association with the European
Concerted Action on Cystic Fibrosis.
** in association with the European
Academy of Andrology.
Table 3: External
Quality Assessment
Schemes for molecular
genetic testing available
in Europe 2000–2001.
‘Expression of Interest’ submitted by a
partnership including EMQN, the EU
recognised this need in a call for proposals
under its 5th Framework Measurement and
Testing programme and the proposed
project to develop CRMs is currently under
negotiation.
Important elements of total quality
assurance in the analytical laboratory are
provided by workforce considerations,
external checks on performance and the
availability of traceable calibrants and
controls (reference materials) but
the assessment of all of these features is
provided by good management practice.
Accreditation for service is therefore a
key to the compliance of the laboratory
in all elements of internal quality control
and external oversight that together
assure the validity of the test result
for the public.
A number of bodies are recognised
as competent to accredit, and many
industrial and public analytical services are
familiar with the ISO 9000 series of
standards, against which the British
C O N T R I B U T E D
Standards Institute (BSI) is the inspecting
agency in the UK. In the world
of medical laboratories the main
accrediting agency is Clinical Pathology
Accreditation (UK) Ltd (CPA). CPA has
developed specific standards relevant
to diagnostic laboratories and has been
accrediting centres since 1992. In the
next two years, revised standards
harmonised with ISO/IEC17025 will be
introduced. These new standards introduce
a more client-centred approach, and the
concepts of a quality manual and the
introduction of a quality manager will be
central to their operation and the inspection
process. To date only about 20% of UK
Genetics laboratories have been accredited
but most are in the process of applying or
have been inspected and are meeting
conditional requirements.
In summary, as a discipline, Clinical
Molecular Genetics in the UK has recognised
the need to assure the quality of genetic testing
in the transition from research to service. It
has adopted all the available systems designed
to assure quality including accreditation, and
registration of personnel. In addition it has
developed some systems with advanced
features including interpretative laboratory
proficiency schemes and linked ‘best practice’
guidelines. Finally it has helped to spread and
harmonise these systems in Europe and to
develop previously unexplored areas such as
the production of Certified Reference
Materials for genetic testing.
REFERENCES
1. Stenhouse, S., and Middleton-Price, H.
(1996) Quality Assurance in Molecular
Diagnosis. 341-353 in Elles, R. (ed)
Molecular
Diagnosis
of
Genetic
Diseases. Humana, Totowa.
2. Dequeker, E., and Cassiman, J.J. (1998)
Evaluation of CFTR gene mutation
testing methods in 136 diagnostic
laboratories: report of a large European
external quality assessment. Eur J Hum
Genet 6(2):165-75.
3. Dequeker, E., and Cassiman, J.J. (2000)
Genetic testing and quality control in
diagnostic laboratories. J.J. Nat. Genet.
25: 259-260.
4. Losekoot, M., Bakker, B., Laccone, F.,
Stenhouse, S., Elles, R. (1999) A
European pilot quality assessment
scheme for molecular diagnosis of
Huntington’s disease. Eur. J. Hum.
Genet. 7(2): 217-22.
A R T I C L E S
Addresses
European Molecular Genetics
Quality Network
c/o Regional Molecular Genetics
Laboratory
St Mary’s Hospital
MANCHESTER
M13 OJH UK
National Centre for Medical Genetics
Our Lady’s Hospital for Sick Children
CRUMLIN
Dublin
IRELAND
UK National External Quality
Assessment Scheme for
Molecular Genetics
c/o Regional Molecular Genetics
Laboratory
St Mary’s Hospital
MANCHESTER
M13 OJH UK
Northern Regional Genetics Service
Claremont Place
NEWCASTLE
NE1 7RL UK
5. Jeffrey, G.P., Chakrabarti, S., Hegele,
R.A., Adams, P.C. (1999) Polymorphism
in intron 4 of HFE may cause
overestimation of C282Y homozygote
prevalence in haemochromatosis. Nat.
Genet.22(4):325-6.
F O C U S
O N
F O R E N S I C
A N A L Y S I S
Standards in evidence –
The registration of forensic practitioners
Alan Kershaw
Council for the registration of Forensic Practitioners
guess I should hesitate to offer a paper
to a scientific publication. I am not,
and never will be, a scientist. But I
am conducting an experiment – one
which has a good chance of succeeding
and which represents some front line
thinking in professional regulation
I
and in the setting of standards for
forensic practice.
Miscarriages of justice
There must be few things that can as easily
go undetected in a criminal trial as a flaw in the
1 3
V A M
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evidence of a forensic expert. And few things
that will as readily bring the criminal justice
system, and the name of science itself, into
disrepute as the revelation that a forensic
practitioner has been incompetent in bringing
their findings to court.
Some high profile cases in the 1970s,
F O C U S
O N
F O R E N S I C
The author.
where flaws came to light many years later,
resonate still in the public imagination. It
would not be an exaggeration to say that
they shook the criminal justice system to its
foundations. Certainly, they cast a long
shadow over the credibility and authority of
forensic experts and the evidence they give
in court. From them there is an unbroken
line to the Council for the Registration of
Forensic Practitioners (CRFP), which has
now opened the first ever register of forensic
practitioners.
Restoring confidence
Trust had to be restored. The courts and
the public deserved the reassurance that the
forensic process was all it should be. The
“Increasingly courts rely on the
objectivity of forensic science. It is
essential that the profession ensures it
provides it. Safer science means
sustainable verdicts. The more powerful
forensic science becomes, the more
confidence society needs in its
practitioners. Currently any Tom, Dick
or Harriet can purport to be a forensic
expert, often providing advice which is
unhelpful at best, and positively
misleading at worst. This register means
something because, unlike all the others,
it is based on peer review and not
customer perceptions.”
Dr Angela Gallop
Director, ‘Forensic Alliance’
and President Elect of the Forensic
Science Society
A N A L Y S I S
forensic science community, much to their
credit, were quick to see the need for this
and took steps to introduce the systematic
practice of quality assurance which is now an
ever-present feature of forensic laboratories,
running through their management and
their processes.
But there was a piece missing, a task
perhaps more difficult to perform but no less
essential to restoring confidence: ensuring that
the individual scientists and others who use
professional skills to produce evidence for court
are, and remain, fit for their job. The forensic
professions settled for external accreditation by
way of a structured, external assessment of the
current competence of individual practitioners.
That is what CRFP now offers.
What CRFP is for
CRFP has been set up with a single,
overriding objective: to promote public
confidence in forensic practice in the UK.
This includes not just scientists but all the
specialist groups involved in the whole chain
of the forensic process, from the crime scene
to the courtroom: scene examiners,
fingerprint examiners, laboratory scientists,
police surgeons, pathologists, dentists, IT
specialists, archaeologists, anthropologists
and all professionals who may contribute to
an investigation and to the presentation of a
successful case.
The public demand – and deserve – to
know that every practitioner in that chain is
competent, and committed to professional
values against which they are prepared to be
judged if something goes wrong.
What CRFP will do
CRFP has three main functions:
• publishing a register of competent
forensic practitioners
• ensuring through periodic revalidation
that practitioners keep up to date and
maintain competence
• dealing with registered practitioners who
fail to meet the necessary standards.
The first of those is the central function,
from which everything else flows. A register
puts a boundary around a profession,
showing who has been assessed as
competent in the field.
The second function is the public’s
assurance that registered practitioners remain
fit to do their job. Registration will be time
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limited, running for four years at a time.
Before the end of that period each person on
the register will have to satisfy us that they
have learned positively from their experience,
kept abreast of developments in their field and
pursued a policy of continuous improvement.
We will fulfil the third function by
dealing, firmly and fairly, with any
information we receive which raises a
question about an individual’s fitness to stay
on the register. There may be an allegation of
misconduct, or a problem of ill health or poor
professional performance. We will deal with
each of these in the way that suits them best.
Standards of conduct
Professional regulation is often
caricatured as the business of striking
dysfunctional practitioners off the register.
In fact, it is much more about helping good
practitioners to stay good and become better
through their careers.
That is why we have published a Code
of Conduct as the foundation of the register.
This is not a guide on how to get into
trouble. It is a clear, positive statement of
professional values. Everyone applying for
registration will have to show they
understand those values and state that they
will adhere to them in their everyday work.
The Code focuses on the forensic
practitioner’s overriding duty to the court
and the administration of justice. Among
other things we highlight the principles of:
• putting justice and the needs of the
court first;
• honesty, integrity, objectivity and
impartiality;
• confidentiality and freedom from
discrimination;
• understanding the limits of professional
confidence – even, perhaps especially,
when under pressure in the witness box.
How registration will work
The register is now open to scientists,
scene examiners, and fingerprint examiners.
We have divided scientists into eight groups,
designed to reflect broadly the thought
processes involved in each specialist area.
The eight groups are drugs, toxicology,
marks, firearms, particulates and other
traces, human contact traces, incident
reconstruction and questioned documents.
F O C U S
For each group we are training a team of
specialist assessors, each of them a competent
practitioner in their field. They will assess
the current competence of applicants from
their professional group, along with their
ability to practise safely and independently.
The assessments will be structured and the
system is designed to secure consistency and
fairness across the sector. We have provided
for second opinions and appeals against a
refusal of registration and the whole process
is subject to external validation by respected
academics.
We are asking each applicant for
information about themselves, their
qualifications and their professional
experience; for a brief portfolio of recent
casework; professional references; and
declarations about their past record and
willingness to adhere to the Code of
Conduct. All this evidence will be judged
against the criteria we have identified to
define competence in each speciality.
The scope of the register
The register will be inclusive, covering
practitioners throughout the forensic process
– from the recovery of material, through its
identification, examination and analysis, to
the presentation of evidence in court. It will
be a single register, identifying the specialist
fields in which each practitioner works – and,
in the case of scientists, the sub-specialties in
which they have their particular interests.
“The Courts have been and are
likely to continue to be increasingly
dependent on the quality of forensic
practitioners who are involved in
proceedings in the Courts. CRFP are to
be warmly congratulated on the efforts
which they are making to encourage
forensic practitioners to adopt the
necessary standards and good practice.
The establishment of a register is very
welcome. It should ensure that those
practitioners who fulfil the required
standards can be identified. It should
encourage those who do not meet those
standards to improve their practice.”
The Rt Hon
Lord Woolf of Barnes
Lord Chief Justice
of England and Wales
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F O R E N S I C
A N A L Y S I S
We have set the fee at £125 a year for
registration in one speciality, plus £15 for
each additional specialty, recognising the
multi-skilling that is a feature of some forensic
organisations. Some of the major employers
have decided to pay the fees on behalf of their
employees who apply for registration.
A new professionalism
At this stage we are focusing on those
who work for the criminal courts. We will
consider later whether to extend our scope
to those working in civil litigation, where
different issues arise and where the case for
accreditation – though strong in our eyes – is
not yet universally accepted.
Who can apply?
The register is open to scientists and
scene examiners who are:
• actively practising in their fields - that is,
not simply organising a department or
managing or training others;
• using professional skills to produce
evidence – oral or written – for use
in court;
• practising in their own right – that is, not
working solely under supervision or
carrying out others’ instructions.
Who pays?
CRFP’s start up costs are being funded
by the Home Office – a powerful indicator of
government support at a time when public
expenditure is under constant scrutiny. In
time they expect us, like other regulatory
bodies, to fund ourselves by making a charge
for registration and the retention of a name
on the register. This is an important
principle in professional regulation:
independence from government is essential
if a scheme is to retain the confidence of
those on the register.
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V A M
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In the current climate, professionals of
all kinds are having to come to terms with
the relatively new, but plain, fact that their
expertise will no longer be taken for granted.
They and their decisions must bear scrutiny
in return for the great trust which society
places in them.
This is not something to be feared. It
calls for a professionalism that welcomes
external assessment, critical review and the
systematic application of quality assurance
techniques. This is how it should be:
regulation is not something a regulatory
body can come out of the blue and ‘do’ to a
profession. Regulation starts with the
individual practitioner and extends outwards
to the teams they work in, their local and
national associations, the bodies that
represent them and the centres of excellence
in which they are trained.
“High quality evidence, professionally
presented, is the key to an effective and
efficient criminal justice system. That
demands high professional standards in
the multitude of specialist disciplines that
come together as ‘forensic practitioners’.
The Government wants to encourage the
best use of expert evidence, which is why
we are supporting the establishment of
CRFP, which is a unique concept and a
real world leader. I believe it will make
an important contribution and wish
it well.”
Charles Clarke MP
Minister of State
at the Home Office
CRFP has a crucial part to play,
both directly and as a catalyst. We offer
forensic practitioners the opportunity to
demonstrate, to anyone who needs to know,
their current fitness for the job they do.
Registration is far more than a bureaucratic
process. It is the expression of a standard
and of a renewed professionalism.
F O C U S
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F O R E N S I C
A N A L Y S I S
We may have to go to court with
this one…
Ric Treble
& Fraser
Nicholson
LGC
rofessional forensic scientists and
expert witnesses expect their work to
be used in legal proceedings, and are trained
in how to conduct their work appropriately,
to prepare statements or reports for court,
and to present their evidence in person
when this is necessary. However, any
analyst could find themselves required or
requested to present their results as
evidence in a court case, criminal or civil.
Sometimes the analyst is warned in advance
that a court case is expected. On other
occasions, what at the time appeared to be a
routine analysis can subsequently become a
component of a legal case. Whatever the
circumstances, there can be understandable
concern for an analyst with little experience
of legal proceedings when a customer
announces that “we may have to go to court
with this one…”
P
…the scientist becoming
involved in legal proceedings
for the first time may feel
they are being invited to
enter this unfamiliar
territory without a map
There are a number of issues to be taken
into consideration when analytical
measurement data is to be used in court,
some procedural, some legal and some
practical. Apart from general conformance
with the VAM Principles, many producers of
analytical measurements for the courts work
to specific guidelines or codes of practice for
undertaking particular types of forensic
analyses. Sector-specific organisations often
align their recommendations with the specific
regulation or legislation for which they are
providing evidence. Many sector-specific and
cross-sectoral organisations also have generic
best practice guidance for their members.
Although there is a range of such best
practice guidance available, the scientist
becoming involved in legal proceedings for
the first time may feel they are being invited
to enter this unfamiliar territory without a
map. After consultations both with scientific
experts with experience in this field and with
legal practitioners who make use of expert
witnesses, it was decided to produce a short
guide 1 to explain some of the key issues
involved and, more practically, to provide
directions to suitable sources of advice
and expertise.
Some key issues
Key background issues of which the
expert needs to be aware when they take on
forensic commitments include:
• The requirement for expert evidence and
opinion to be reliable.
The privileged status and weight accorded to
expert evidence makes a clear moral case for
any expert evidence presented to be
dependable. More practically, any court
case, no matter how dignified the procedures
appear, is a fight between two sides and all
evidence is open to challenge. A scientist
offering expert evidence or opinion must
therefore be able and prepared to
demonstrate, sometimes under aggressive
questioning, that their work was valid.
• The overarching requirement for the
expert to be impartial.
The expert’s responsibility is to the court, not
to the side providing their instruction and/or
payment. This principle has been clarified in
a number of key cases, including ‘the
Ikarian Reefer’2 (which was a ship, not an
exotic cigarette) in the civil courts and the
Judith Ward judgement3 in the criminal
courts. It is now also spelt out in a number
of legal and professional Codes of Conduct.
• The need for timely provision of evidence.
Delays, and subsequent costs, have been
identified as key problems within the legal
system. Major initiatives, including the
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V A M
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Woolf Reforms in the civil courts and the
Narey Reforms in the criminal system, have
been established to tackle these problems.
The expert has to play their role by agreeing
a time-scale for their work and ensuring
that this time-scale is met.
Expecting to be challenged
and the importance of validity
In an adversarial legal system, such as
ours, analytical measurement evidence being
presented in court must be expected to be
subject to challenge, in exactly the same way
that all other types of evidence can be
challenged. This has traditionally been
achieved by the appointment of a suitably
qualified expert to act for the other side in
the case. It is therefore vital that analytical
measurement data produced for use in court
are as valid and reliable as possible.
The producers of analytical
measurement evidence that may
be used in legal proceedings
therefore need to know what
standards of validity will be
expected of them.
The producers of analytical measurement evidence that may be used in legal
proceedings therefore need to know what
standards of validity will be expected of them.
In addition, the users of the analytical
results, that is the legal profession and the
judiciary, also need to be aware of any
factors that may increase, or decrease,
confidence in the reliability of results. Legal
professionals can become extremely annoyed
if the expert they are using to develop their
case decides to backtrack on the reliability of
the evidence, or to start qualifying their
evidence at a late stage. The basis of
analytical evidence therefore needs clear
explanation so that its validity and
significance can be considered while the case
is being prepared.
In practice, analytical measurement is
currently only rarely challenged or questioned
F O C U S
in depth in court. There is increasing reliance
on pre-trial disclosure of expert evidence, so
that issues can be identified and addressed by
the two sides before the court convenes. If
agreement can be reached on the majority of
technical matters outside the court, only
genuine issues of dispute between the two
sides need to be decided by the court. In
addition, the expert often finds that it is issues
other than the measurements themselves,
which are being questioned, such as chain-ofcustody details or possible alternative
explanations for the findings.
Although an expert might hope that their
evidence will be unchallenged, this approach is
potentially dangerous in that the court will be
asked to draw conclusions based on
information, the detail and reliability of which
may not be fully explored. There is therefore a
responsibility on the expert to ensure that any
findings to be used in a court case are valid.
Contents of the guide
The contents of the guide are
summarised below. It is structured as a
series of sections, setting out key issues and
directing the interested reader to appropriate
sources of further information and advice.
Where possible, the guide’s references are to
suitable websites, in order to try to provide
rapidly accessible information and advice for
analysts who find themselves faced with the
prospect of involvement in a legal case and
who may not have time to seek out the more
traditional paper-based resources.
The English legal system
The guide opens by addressing the
English legal system. This is an extremely
complex subject, so readers are directed to
some of the more approachable introductions
that have been prepared for the benefit of the
novice expert about to become involved in
legal proceedings. The guide does however
explain some of the more common terms
used in the Magistrates, Crown, County and
High Courts.
The role of the expert
The guide then moves on to address the
role of the expert within the legal system.
The key legal difference between the expert
witness and all other witnesses in a case is
that the expert is allowed to present evidence
of opinion, as well as evidence of fact. They
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F O R E N S I C
are allowed to do this in order to assist the
court to understand matters that are not
within the common knowledge of the court.
…there is a particular
responsibility placed on the
expert, in that they have
to regard their role as acting
for the court, irrespective
of which side in the case
is instructing them
This means that there is a particular
responsibility placed on the expert, in that
they have to regard their role as acting for
the court, irrespective of which side in the
case is instructing them – and is paying their
fees. There are other issues that the expert
witness has to consider, and the guide
provides references to a number of detailed
codes of conduct for expert witnesses which
have been published by professional bodies.
How experts are
identified and engaged
If a court case develops from analytical
work carried out under an existing contract, the
expert and their work are subsumed into the
legal process. However, where expert witnesses
are sought by solicitors to assist in cases,
they are usually identified either by entries in
directories or registers of experts, or by word of
mouth. As well as advertising their services by
means of one or more of the directories, an
expert who acquits themselves well in court will
be remembered by the solicitor employing them
and can usually expect to be re-engaged by the
same and other solicitors when similar cases
arise. When invited to assist in a case, the ‘terms
of engagement’ need to be carefully agreed
– even when there is pressure for a quick
response. Issues to be addressed include the
timetable required and the suitability and
limits of the expert’s knowledge for the
issues in question. Sources of advice on
engagement issues and standard contracts
for engagement are available.
Chain-of-custody
and contemporaneous
note keeping
There are a number of particular
requirements for work to be used in court 1 7
V A M
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A N A L Y S I S
particularly in criminal cases where the
standard of proof required is ‘beyond
reasonable doubt’. (In civil courts, by
contrast, cases are decided ‘on the balance of
the probabilities’). One of the most
important requirements is the ability to
demonstrate chain-of-custody. For analytical
work, this refers to documentary evidence
that the data presented refer to the original
item of interest, and that the item has been
in safe custody throughout the process, so
that its integrity has been maintained.
One of the most important
requirements is the ability to
demonstrate chain-of-custody.
The guide reviews the various aspects of
this process and the requirement for the
keeping of contemporaneous records of work
carried out, either by means of written notes
and laboratory records or, in circumstances
where making written records is not
practical, by audio or video-tape records.
Selection of methodology
Use of validated methodology is extremely
important as a means to demonstrate to the
court that findings and opinions are soundly
based. The more robust the evidence of the
method’s conformity with the VAM
principles, the less likelihood there is of the
other side’s expert recommending a challenge
over the validity of results. For routine testing,
using methods subject to independent
accreditation by bodies such as UKAS
provides strong evidence of validity. For nonroutine work, where accreditation is not
appropriate or practical, the use of standard
published methods which are accepted in the
relevant sector is advisable. However, in those
cases where methods have to be adapted or
developed specifically for the task, appropriate
validation evidence will need to be compiled,
and the EURACHEM Guide to method
validation can provide useful advice.
Retention and
disposal of material
The retention and disposal of evidential
material and records needs to be carefully
managed, material may be needed for
subsequent appeal or review. As a general
rule, no evidential documentation or
material should ever be disposed of without
the customer’s written authority, and any
F O C U S
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F O R E N S I C
disposal of material should be documented,
including the return of items to customers.
Explaining the
significance of findings
The significance of results should be
explained by placing the findings into
context. This is particularly true where
‘matches’ or similarities between items are
being reported, and where population
statistics therefore become important. For
example, finding that two pieces of
commercially available adhesive tape are
made of the same materials is unlikely to be
of any great significance, as millions of rolls
of such tape may be in circulation. However,
establishing an exact physical match between
two torn ends of tape in different items in a
case could be extremely significant. In recent
years, Bayesian statistics has become
increasingly widely applied to clarify such
issues, led particularly by the need to explain
the significance of DNA results. This
powerful technique, based on the
comparison of probabilities, is strongly
recommended where the significance of
results is likely to be an issue, and suitable
reference sources are recommended in the
guide. However, this is not a simple
technique to master and the assistance of a
statistician may have to be sought to clarify
the complexities involved.
Uncertainty and proof
Associated with the issue of significance is
the question of analytical uncertainty.
Analysts are expected to be aware of the
degree of uncertainty inherent in their results,
and should clearly communicate this to the
lawyers engaging their services so that they
can decide on the use which can be made of
the results. Similarly, an expert acting for the
other side in a case can be expected to assess
the degree of uncertainty in the results as part
of their review of the findings. A common
concern is that results which are to be
reported as having a 95% or 99% confidence
level may therefore be regarded as unsuitable
for use in a criminal case where the standard
of proof is to be ‘beyond reasonable doubt’ .
However, this standard refers to the need to
establish proof beyond reasonable doubt
based on the whole of the evidence produced
by both parties in the case – not for each
individual item of evidence involved.
A N A L Y S I S
Sampling
Sampling issues can vary from the need to
collect a truly representative sample from a bulk
consignment – for which statistically based
guidance is available – to collecting an unique
item from a crime scene. In both cases,
contemporaneous documentation of the
procedures followed to collect the sample and to
avoid any contamination needs to be retained
for subsequent examination if required.
Sealing of items
In order to demonstrate that the integrity
of materials that have been sampled or
submitted has been maintained, it is common
to use tamper-evident methods of sealing or
securing items. These allow the analyst to
attest that the items have not been interfered
with while they were in transit to or within the
laboratory, or while stored under their
control. Advice is included as to how this can
be achieved in practice, either by using
custom-designed ‘tamper evident evidence
bags’ or by techniques such as sealing under
signature. Again, detailed record keeping is
advisable, so as to be able to show who had
access to the sample, and at what time.
Creating a case file
It is good practice to create an indexed
file containing all the paperwork relating to a
sample or case, including notes, instrument
output, calculations etc. This not only helps
to avoid any loss of material, but also
facilitates disclosure of case material .
Preparing reports
and statements
The guide provides directions to sources
of information on how statements and
reports should be drafted for use in criminal
and civil courts. The need to balance clarity
for the non-scientific reader with a full
exposition of the analytical issues requires
careful composition. The courts prefer
experts to adopt a standardised format to
assist readers of such documents to find their
way around the text. Analysts are also
subject to some specific legal requirements
covering issues such as hearsay. In practice,
this requirement can usually be met by
disclosure of the role played by assistants
who have worked under the direction of the
1 8
V A M
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analyst. The other side can then decide
whether they wish to question the assistants
as well as the analyst.
Disclosure
As mentioned previously, pre-trial
disclosure of expert’s findings is now
routine. Examination of evidence and, where
necessary, pre-trial meetings of the experts
from the two sides are intended to settle as
many areas of disagreement as possible
before the trial, so that only any remaining
areas of disagreement have to be presented
to and decided by the court. The procedure
for disclosure differs between civil and
criminal cases, and the details are normally
attended to by the lawyers involved in the
case. However, the responsibility remains
with the analyst to ensure that the lawyer
acting for their side of the case is aware of
the existence of disclosable material.
Preparing for Court
Appearances
The final and, for the novice, often the
most worrying, stage in the process is to
prepare oneself to present evidence in court.
The guide includes directions to sources of
advice and, for those who anticipate a
number of appearances as expert witnesses,
organisations providing training courses in
the ‘art’ of court presentation.
It is hoped that the guide will form a
useful introduction to the issues involved in
taking analytical measurements to the court,
and provide analysts unfamiliar with the
requirements of court work with directions
to suitable sources of references to prepare
them for their role in the dispensation
of justice.
REFERENCES
1. VAM Report LGC/VAM/2000/062, Legal
aspects of analytical measurement,
undertaking analytical measurement for
court – A good practice guide for
scientists, (2000)
2. The Ikarian Reefer (1993), 20 FSR 563
3. R v Ward (1993), 1 WLR 619, 96 Cr.
App. Ref. 1, 2 All ER 577, Court of
Appeal (criminal Division).
F O C U S
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A N A L Y S I S
Useful web sites for background information
Organisations supporting forensic experts:
The Academy of Experts
The Expert Witness Institute
The Council for the Registration of Forensic Practitioners
The Forensic Science Society
The British Academy of Forensic Sciences
The Society of Expert Witnesses
www.academy-experts.org.uk
www.ewi.org.uk
www.crfp.org.uk
www.demon.co.uk/forensics/
www.lawsoc.org.uk
www.sew.org.uk
Directories of Expert Witnesses:
Expert Witness – Expert Consultant
The Law Society of England and Wales
UK Register of Expert Witnesses
www.expertwitness.co.uk
www.lawsoc.org.uk
www.jspubs.com (Includes links to useful sites for experts)
Court Skills Training:
Bond Solon Training
Professional Solutions and Services Ltd
www.bondsolon.com
www.prosols.uk.com
Other useful sites:
The Criminal Justice Joint Planning Unit (CJJPU)
Eurachem website
Valid Analytical Measurement (VAM)
RSC Code of Conduct and Guidance on Professional Practice
www.criminal-justice-system.gov.uk
www.vtt.fi/ket/eurachem
www.vam.org.uk
www.rsc.org
C A S E
S T U D Y
This issue of the VAM Bulletin contains the seventh of a series of case studies, demonstrating the business benefits of VAM. Companies often perceive the
merit in sharing their own stories of the tangible benefits of the VAM approach. It is hoped that this articles will provided enough detail to be of value
beyond the industrial sector directly involved, to a wider range of businesses engaged in analytical science.
The development of an industry – based PT
scheme and the benefits of participation
Dr Roger S. Brown
Source Testing Association
Rod A. Robinson
National Physical Laboratory
Summary
T
he Source Testing Association (STA)
has adopted a proficiency-testing (PT)
scheme for gas measurement as a service to
its membership. This scheme will help ensure
that members offering gas measurements
meet the minimum requirements of its code
of practice. It will also satisfy the requirements
of Quality Assurance Schemes accredited by
UKAS. The PT scheme has been developed
for the STA by the National Physical
Laboratory (NPL) and has been
underpinned by the DTI’s Valid Analytical
Measurement (VAM) Programme.
This article puts the Association into
perspective and discusses the logistics of the
scheme that has been subsequently
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developed from an initial trial to a fully
operational scheme offered to our
membership. The scheme reassures the
clients of our members that the data
submitted to legislative bodies has validity.
This article discusses the fruitful partnership
the STA has formed with NPL in developing
a Gas Analysis Proficiency Testing Scheme.
The Source Testing
Association
To understand the reasons why
a proficiency testing scheme is important
to the members of the STA it is important
to understand a little of the STA’s
history, structure, its codes of practice
and its endorsement programmes.
C A S E
S T U D Y
We initially took as our model the
Source Evaluation Society (from the USA),
and developed a Code of Practice that
members must sign up to on joining the
Association. We established a constitution,
set rules for membership, established an
organisational structure, and launched the
Association in 1996 as a non-profit making
organisation.
Although the Association started life as a
trade association for those directly involved
in source (stack) testing our recruitment
drive gave us a much wider membership and
our current membership consists of the
following groups:
• test Houses (50%);
• regulators (5%);
• process Operators (15%);
• instrumentation Companies (25%);
• gas suppliers (5%).
The STA was set up in 1995 to meet a need
to improve the quality of emissions testing
and monitoring in the UK.
Industrial air pollution has been
regulated in the UK since the first Clean Air
Act of the 1950s. The Environmental
Protection Acts of 1990 and 1995 require
operators to prove to the Enforcement
Authorities that their process complies with
the relevant Prescribed Processes Regulations.
This principle continues with the latest
Integrated Pollution Prevention and Control
(IPPC) regulations, which came into force
this year. In all these regulatory instruments
the ‘Polluter Pays’ concept operates.
It is crucial that valid measurements are
made, and that process operators and
regulators have confidence in the data they
receive from the test houses (i.e.
organisations who undertake emission
measurements).
The mission statement of the Source
Testing Association is to:
“Advance the science and practice
of emission monitoring and to develop
and maintain a high quality of service
to customers.”
I
II
SEPA: Scottish Environment Protection Agency
NIHES: Northern Ireland Industrial Pollution
and Radiochemical Inspectorate
The STA has developed a programme of
seminars and workshops and through these
and other activities has developed links with:
• The Department of Trade & Industry
(& in particular the VAM Programme);
• Department of Environment, Transport
& the Regions (DETR);
• The Environment Agencies EA, SEPAI,
NIHESII;
• The United Kingdom Accreditation
Service (UKAS);
• The Chartered Institute of Environmental Health Officers (CIEHO).
The STA is organised such that each area
that is important to the practice of emission
monitoring has its own task group (working
party). This ensures that key matters within
that area are addressed. The task groups
currently in operation are listed in Table 1.
Task Group
Date Formed
Technical Task
Group (TTG)
1996
Endorsement Sub Group
1997
Standard Review
Sub Group
1999
An Instrumentation
Task Group
2000
Health & Safety
Task Group
1997
Quality Task Group
1996
Marketing Group
1999
Small Business
Task Group
1996
Table 1: Task groups
currently in operation.
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Each Task Group has its own remit and
develops strategies that are considered by the
management group before being put forward
to the membership.
The Drive For Quality
To satisfy the need to improve quality,
in 1996 the STA Technical Task Group &
Quality Group approached the VAM key
players (NPL, LGC, UKAS) and on
November 7, an STA workshop was arranged
in Stoke on Trent.
The key point, which arose from the
VAM meeting, was that our members and
the Association should adopt the VAM
principles [See Page 2].
In general, these tenets were mirrored by
some of our own stated codes of practice,
which are that members who conduct stack
testing should:
1. use the correct method;
2. use the correct equipment;
3. use equipment which is calibrated;
4. utilise competent personnel;
5. operate to documented protocols;
6. operate the equipment correctly;
7. operate to a quality system;
8. implement risk assessment
& health & safety policies;
9. participate in proficiency
testing schemes.
Following the meeting in Stoke, the STA
committed itself to establishing a series of
endorsement programmes and starting a trial
proficiency testing scheme.
The Endorsement and
Gas Analysis Proficiency
Testing Scheme
The STA was founded on the principle
that its members must abide by its code of
practice and achieve at least minimum
standards of conduct (which are documented).
To assist in demonstrating this to clients
of our members, it was decided to operate a
number of Quality Assurance endorsement
programmes. These consisted of peer review
of the member applying for endorsement for
a class of tests, be it for dust or gaseous
measurement. The STA then convened a
panel to consider the submitted protocols
against BS CEN and US EPA methods and
arranged a site appraisal of the sampling
teams on a rolling basis.
C A S E
The STA set up a series of endorsement
schemes to allow on-site peer review of
members. In 1998 the STA launched its first
endorsement programme for particulate
testing of source emissions from industrial
facilities. Currently thirty member
companies participate in this scheme. In
1999 we launched our measurement scheme
by instrumental means for carbon monoxide
(CO), carbon dioxide (CO 2), nitric oxide
(NO), oxides of nitrogen (NOx), sulfur
dioxide (SO2) and volatile organic compounds
(VOCs) and we currently have 11 member
companies who have enrolled in this
latter scheme.
The verification of quality in source
testing is very difficult because, in general,
the emissions on a process can vary due to a
number of different factors. These include,
changing feedstock, varying operating
conditions, changes in flue gas velocity etc.
Unless a series of simultaneous trials with
co-location of sampling probes is conducted,
it is almost impossible to verify data directly;
even then across a stack there can be
significant variations in concentration levels.
Tests such as these are very expensive and
few clients would be willing to pay the costs.
One way of addressing these difficulties
is to operate one or more PT schemes.
These allow inter-comparison against round
robin samples and give an indication of
inter-company variations. This can then
provide input to the endorsement schemes.
Schemes such as this also have significance
to UKAS accredited companies, as UKAS
accreditation to ISO 17025 requires
participation in PT schemes where they
exist. In the future, PT schemes will
undoubtedly play their part in personnel
competency schemes such as the
Environment Agency’s, “MCERTS Scheme
for Manual Stack Testing”.
In order to trial a PT scheme the STA
formed a link with the National Physical
Laboratory (NPL) and asked Dr Peter
Woods’ group to run a trial proficiency
testing scheme for gas analysis. This trial
was operated by NPL and funded as a part
of the VAM Programme by the DTI.
In this trial scheme a set of 5 commercial
gas cylinders were labelled by NPL traceable
to UK national standards. The STA
approached its members to seek
participation in the scheme, eighteen
companies within the STA agreed to
participate and in the end sixteen companies
returned results for statistical analysis.
The logistical arrangements of
preparing, shipping, supplying regulators
etc., cannot be under estimated and in many
ways has turned out to be more taxing for
the STA and NPL than the science involved.
The approximate gas concentration was
identified to the company but not all
companies analysed all cylinders due to
different capabilities and the availability of
equipment and staff.
The gases that were circulated are
shown in Table 2.
Species
Nominal Concentration
CO in Nitrogen 2%I, 1000 ppmII, 100 ppm
NO in Nitrogen 500 ppm
SO2 in Nitrogen 1000 ppm
Table 2: Gas cylinders
distributed by NPL.
The scheme was in the process of being
developed during the trial and a fully defined
protocol was not available. It had not been
stipulated how participants should introduce
the gases to their analysers. Thus some
companies would introduce the gases directly
to a gas analyser, whilst others would introduce
the test gases to the analysers via a gas
conditioning system. Some systems needed
less than one litre of gas per minute of gas
whilst others would require several litres of gas
per minute from the supplied gas cylinders.
In addition it must be remembered that
the gases shipped were very different, in
their presentation, from those sampled in the
field. The gases in a stack are often hot and
may be present in conditions ranging
from relatively dry to extremely wet.
Condensation combined with high levels of
dust and the presence of many other species
can often cause sampling and analysis
complications.
However, the pure binary mixture gases
were a first attempt to consider the intervariability of companies involved in the
source-testing field. The gases were
distributed around the participating members
free of charge over a period of 6–12 months,
and the results collected and collated by NPL.
What happened next – The
good, the bad and the ugly?
The overall results from the scheme
were encouraging with only one organisation
falling into an unacceptable category. The data
were processed and analysed by NPL and a
summary of the data is shown in Figure 1.
As an example, NPL also processed the
data on the basis of z-scores as this enables
criteria of acceptability to be set more easily
and allows interpretation of the data at low
concentrations to be assessed more fairly. A
small error in measurement is more apparent
at the lower concentration levels and results
in a relatively higher percentage difference.
In this study the z score was defined as:
x–T
z =
σ
Where:
z = the z score
x = the value obtained by participant
T = the true value for test sample
σ = the assigned value for the
expected standard deviation (for
the purposes of this example this
was derived from the requirements of the EU Hazardous
Waste Directive)
The criteria for acceptability in the PT Scheme
was set as:
|z| ≤ 2
Satisfactory
2 >|z|< 3 Questionable
|z| ≥ 3
Unsatisfactory
I
2 1
V A M
B U L L E T I N
S T U D Y
II
% ≡ 10 mmol mol-1
ppm ≡ µmol mol-1
C A S E
S T U D Y
Figure 1: Percentage difference in gas concentration of the
measured result versus the true level in the cylinder.
Figure 2: The range of variability in the ‘Trial Gas Proficiency
Scheme’ in terms of z-scores.
The data are represented in this format
in Figure 2.
As mentioned earlier, the data analysis
showed that only on one occasion was one
member company yielding an unacceptable
result. Full details were not available, from
many of the companies, on the procedure
they adopted in analysing the gases shipped
to them, so further comment was not possible.
The STA/NPL had asked the participating
companies to quote uncertainties associated
with their analyses but most companies did
not provide this on submission of their data.
Even so, the data were sufficiently encouraging,
and the response from our members overwhelmingly supportive, that the STA has
adopted a full PT scheme for gas analysis.
This scheme is operated by NPL and the
Gas
Species
Nominal
Concentration
1
Sulfur Dioxide
1000 ppmI
2
Sulfur Dioxide
100 ppm
3
Carbon
Monoxide
1000 ppm
4
Carbon
Monoxide
100 ppm
5
Oxides of
Nitrogen
500 ppm
6
Oxygen
11%II
7
VOC control
mixture
~ 4 mg m-3 (TOC)
Table 3: Species to be
measured in NPL/STA
PT scheme.
The STA will continue to manage and
refine the gas analysis PT scheme in
partnership with VAM and NPL to meet the
needs of regulators and members alike. It is
essential to ensure that the NPL/STA
schemes can be harmonised with
Environment Agency schemes such as
MCERTS and also UKAS requirements to
minimise any needless expenditure by our
members.
The STA has decided that the scheme is
certainly a useful mechanism in
demonstrating proficiency in gas analysis
and is currently developing a PT scheme for
flow measurement to assist in other STA
endorsement programmes.
The NPL/STA PT scheme has provided
a further method by which the STA can
continue to provide value-added services to
its membership.
STA and it receives some DTI support
through the current VAM programme.
To date fifteen companies have agreed
to join and currently two sets of gases are
being circulated.
These two sets of gases have been
certified by NPL and are being shipped by
BOC to STA participants. UKAS are
following the progress of the scheme and our
members recognise the value of the scheme
in helping to maintain credibility to clients
and their peers.
A fully operational PT scheme has now
been established for the STA. Following
discussions within the STA the range of
species has been altered slightly and the
nominal values for the scheme are shown in
Table 3.
I
2 2
V A M
B U L L E T I N
II
ppm ≡ µmol mol-1
% ≡ 10 mmol mol-1
V A M
I N
E D U C A T I O N
Taking the VAM message from school
to the workplace
t is important that the UK has a
competent workforce able to meet the
challenges posed by new technologies and
enable sustainable development of the
chemical industry. Analytical scientists are a
pivotal part of this workforce. The new
VAM programme hopes to address some of
the issues and facilitate improvements where
they are necessary.
The need for reliable measurements and
the means by which they are obtained
should be incorporated early in the
education process; therefore the projects
span from school level to the professional
analysts. How early is a matter of debate
now that science forms an integral part of
primary education.
It is important to make students aware of
the contribution that chemical measurements
make to the national economy and the
impact they have on our quality of life.
Within the programme there is provision to
address these issues. There will be events for
teachers to enhance their awareness of how
to obtain valid results and then how to
demonstrate their reliability. We will
continue to organise with Nuffield
curriculum projects an annual Proficiency
Testing competition for students studying
chemistry at A level. This titration exercise
has proved very popular in the past and we
have over 80 schools/colleges showing
interest this year. We are starting to explore
the possibility of a similar competition in
biology. A number of teachers have indicated
their interest in developing a suitable
competition that will fit in with the syllabus.
Increasingly University departments are
including Quality Assurance and Quality
Control topics in their course programmes.
I
We are pleased about this. However, in
most cases these are at the Master’s level
and only in analytical chemistry MSc
programmes. We hope to increase the
coverage into chemistry courses. Another
new venture for MSc students, in
analytical and environmental science, is an
opportunity for them to take part in a round
of a national Proficiency Testing scheme.
This will provide them with valuable
experience with very little cost to the
university, as entry will be free. They will be
sent samples of solids and solutions to
analyse and their results will be compared
with those from commercial laboratories.
We will provide the universities with detailed
feedback in the hope that it will help in
course development and assessment.
During the 1997–2000 VAM
programme a network group was formed
from analysts in SOCSA (Specialised
Organic Chemicals Sector Association)
companies. The ‘SOCSA Analytical
Networking Group’ (SANG) meets about 4
times a year. The meetings have followed a
variety of formats but currently one of the
main items on the agenda is a discussion of
analytical results obtained for a sample
distributed between meetings. This is a
simple benchmarking exercise that helps
identify best practice and resolve the
problems that may arise during the analysis.
This group of companies has accrued
many benefits from the network. These
include:
• development of training packages;
• setting acceptable and achievable
performance parameters;
• access to documentation to help set up
their own quality system;
2 3
V A M
B U L L E T I N
•
involvement of junior analysts with
analysts in other companies;
• benchmarking of skills;
• identification of analytical experts;
• advice on new equipment and servicing;
• best practice in many areas of analytical
science.
In the current programme there is an
opportunity to set up other similar networks
either in different regions (SANG members
are mainly in the North East) or in a
different sector. Identifying SMEs that
would like to be involved in the project is
not straightforward. We are very anxious to
hear from anyone who would like to
participate in such networks. We hope that
university departments will also be part of
the new networks. It is important that there
is a good dialogue between academia and
industry. The intention is to identify training
needs, develop new training materials and
set up a coaching system. It is important that
academia are in on the discussions.
Method development and validation are
important and time-consuming tasks in
analytical science. There is a programme that
will investigate cost effective methodology,
again the needs of industry and particularly
SMEs will be sought.
The programme is varied but has the
general theme of quality of measurement
and dissemination of best practice. The
output of a programme is always more
valuable to users of that output if they are
involved during the programme. Many of
the contacts are made by word of mouth so
if you know of anyone who can contribute to
any of the projects or wish to take part in the
events please contact us through the VAM
Helpdesk (page 2 and 32).
V A M
N E W S
Notes on applying ILAC guidelines to
microbiological PT schemes now available
roficiency testing has become a
principal quality assurance tool for
many laboratories. Most laboratory
accreditation bodies now expect, if not
require, participation in a relevant
proficiency testing scheme if one is available.
Proficiency testing results have become an
important factor in the assessment of a
laboratory’s performance by accreditation
bodies, the laboratory’s customers, and the
laboratory itself.
While proficiency testing schemes have
become key to assessing the competence of
analysts, until recently there has not been
any widely accepted detailed guidance on
competence for the providers of those
schemes. ISO Guide 43-1:1997 and
elements of other standards gave general
guidance, but there has not been anything
suitable for accreditation bodies to assess
proficiency testing scheme providers. The
recently published ILAC-G13:2000,
“Guidelines for the Requirements for the
P
V A M
P R O D U C T
Competence of Providers of Proficiency
Testing Schemes”, has remedied this
deficiency.
The ILAC guidelines have been well
received. A number of accreditation bodies,
including UKAS, are using them as a basis
to develop accreditation services for
proficiency testing scheme providers. One of
the advantages of the Guidelines is that they
are not specific to any field, applying as well
to chemistry as to physics.
This writer has recently raised issues
that are special to microbiological analysis,
making it difficult to apply criteria in the
same ways as to other disciplines1. He has
suggested that such issues do not absolve
microbiology laboratories from requirements
to adhere to criteria, but that they must be
taken into account when assessing how
requirements are met.
At the request of the VAM Proficiency
Testing Working Group the Campden &
Chorleywood Food Research Association
convened an ad hoc working group to
consider special issues in the application of
the ILAC Guidelines to microbiological
proficiency testing schemes. They produced
a short document to be read in conjunction
with the ILAC Guidelines. The topics
covered include:
• homogeneity of microorganisms in the
sample;
• stability;
• sample matrix;
• statistical design.
The notes should help those applying the
ILAC Guidelines to microbiology take
account of appropriate special issues, and
are intended to be widely available via the
VAM Bulletin and the VAM web site.
REFERENCES
1. Microbiological Proficiency Testing:
A Personal Perspective, Jewell, K.,
Accreditation and Quality Assurance,
In Press.
N E W S
Computer-based training package
introduces market’s first measurement
uncertainty module
GC has recently launched VAMSTAT II:
a new edition of its successful,
computer-based learning package for
teaching statistics to analytical chemists.
The new version benefits from a complete
revision and update, and is designed to run
under MS Windows 9x/NT. A key
innovation is the inclusion of a measurement
uncertainty module, a first in the market and
introduced as a direct response to the
growing pressures from accreditation bodies
to see labs making this information available
for customers and for audit purposes. Other
L
new features include more, improved
animations, interactive techniques, an
extensive glossary and a bookmark facility.
“Escalating demands from customers
and regulators for quality in analysis have
increased the need for analytical scientists to
be proficient in the use of basic statistics,”
said Steve Ellison – Head of LGC’s Statistics
and Chemometrics group, and a co-author
of VAMSTAT II. “Building on the sound
statistical information and effective self-test
facilities of the previous version, the new
VAMSTAT release adds better graphics and
2 4
V A M
B U L L E T I N
more interaction to improve learning,
simpler navigation for ease-of-use, and new
information on analytical quality and
measurement uncertainty to help analysts
meet regulatory and customer requirements
in full.”
The principal technical author of
VAMSTAT II was Michael Thompson,
Professor of Analytical Chemistry at
Birkbeck College (University of London),
who originally conceived the VAMSTAT
programme. An acknowledged expert in
applications of statistics in analytical science
V A M
and quality issues, Prof. Thompson has
twenty years experience in teaching statistics
to analytical chemists. With additional input
from practising analytical chemists, and the
inclusion of ‘true-to-life’ examples,
P R O D U C T
VAMSTAT II provides grounding in all the
statistics needed in the modern analytical
chemistry laboratory. It requires minimal
prior knowledge from the student and is
suitable for workplace self-instruction or as a
supplement to formal teaching courses and
the remote-learning format makes for a costeffective solution to increase staff proficiency
in the use of statistics.
VAMSTAT II is divided into seven
sections, each of which contains a number of
self-contained sub-sections dealing with
specific topics. The main areas covered are:
• Basic concepts;
• Significance tests;
• Handling non-normal data and outliers;
• Analysis of variance;
• Quality of analytical data;
N E W S
•
•
Regression and applications;
Measurement uncertainty.
The package is suitable for use by those
with little or no experience of statistics as
well as the more experienced practitioner.
The techniques, practical examples and
questions presented are all strictly related to
the needs of the analytical chemist. Most
sections are supplemented by questions that
test the user’s understanding of the material
presented and the user is free to follow the
topics and build up concepts in their natural
sequence or to pick and choose topics as
required.
For further information contact the VAM
Helpdesk (Pages 2 and 32) or the VAM web
site, where a demonstration version of
VAMSTAT II has been posted by LGC.
Buying analytical services
egular visitors to the VAM web site will
have noticed that a new item appeared
on the navigation menu, late last year.
Clicking on this new arrival, the ‘Buyer’s
Guide’ takes the visitor to a satellite web
called ‘Buying Analytical Services’. This has
been created as a resource to assist those
who need to purchase such services.
One important piece of advice constantly
reiterated is the need for analysts to engage in
dialogue with their customers in order to obtain
a clear understanding of the customers’
requirements (VAM Principle 1 – Page 2).
Advice of this nature is encapsulated in the
VAM Principles, which form the bedrock
upon which the entire VAM Programme is
built. The VAM Programme has hitherto
concentrated on providing tools and support
to analysts to help them maintain or improve
the quality of their measurements and this is
still a primary function. However since, as the
saying goes, ‘it takes two to tango’, it seems
appropriate to offer some complementary
advice to potential customers for analytical
services to help them become better informed
about the nature and process of analysis.
This will hopefully benefit both customers
and analysts since it will guide customers into
thinking along similar lines to the analyst,
in terms of establishing requirements.
This should make for a more efficient
discussion of the analytical problem and its
possible solutions. A further benefit to
R
buyers/customers of measurements is that the
Guide should help them to avoid overspecifying their requirements and could, in
some cases, lead to a reduction in the cost to
them of analysis.
The Buyer’s Guide encourages users to
think about purchasing analysis in terms of
four main strands:
• defining the purpose – clarifying why
analysis is required;
• defining the requirement – stating
what is to be measured;
• defining any constraints – what could
limit the extent or type of analysis
performed;
2 5
V A M
B U L L E T I N
•
selecting a laboratory – how to find a
suitable laboratory to carry out the work.
The guide also contains a ‘Resources’
section which includes a risk assessment test,
advice on the nature of analysis, information
on useful contacts and links to other
organisations, a model ‘requirements’ form
that can be downloaded and a glossary. In
addition, a feedback form allows users to
comment about the site and it is hoped that
they will take the opportunity to do so.
The Buyer’s Guide will be an integral part
of the new VAM website, which is currently
under construction, and may be further
developed in the light of user responses.
I N T E R N A T I O N A L
N E W S
IMEP®: Bringing SI-traceable values
to field laboratories
Jørgen V. Nørgaard
Lutgart Van Nevel
Yetunde Aregbe
Ioannis Papadakis
Philip D. P. Taylor
IRMM, Belgium
nowledge of the degree of equivalence
of analytical measurement results is
important for economical, environmental
and political reasons world-wide. The
International Measurement Evaluation
Programme (IMEP) offers to field
laboratories reference values traceable to Le
Système International d’unités (SI) of
measurements and hence participating
laboratories can evaluate their degree of
equivalence independently from other
participants results. The programme is coordinated by the Institute for Reference
Materials and Measurements (IRMM) and
is run under the auspices of IUPAC,
EURACHEM, EUROMET, CITAC and
EA. The certified test samples with
undisclosed values are sent to interested
laboratories. The participating laboratories
are asked to return their measurement result
with a statement of uncertainty. By
displaying, in pictures, the results from the
participants against the IMEP SI-traceable
reference values, IMEP demonstrates the
State of Practise (SoP) of chemical amount
measurements in various fields. An example
is given for IMEP-14, Trace Elements in
Sediments (Figure 1).
IMEP has different objectives, on
purpose, than traditional round robin studies
or proficiency testing schemes. The values,
which will serve as references, are obtained
by means of well-understood measurement
processes. These reference values are not
derived from and therefore do not depend on
the participant measurement results1. The
IMEP reference values are established mainly
by Isotope Dilution Mass Spectrometry
K
I
II
ISO International Organisation for Standardisation
BIPM Bureau International des Poids et Mesures
(IDMS) applied as a Primary Method of
Measurement (PMM2). The IMEP reference
laboratories are selected specifically for each
IMEP round depending on the material,
matrix and elements under investigation. All
IMEP reference laboratories have shown in
previous work their capability, e.g. by
publications in renowned international
scientific journals.
Other characteristics of the IMEP
programme are that participating laboratories
work under normal conditions with their
choice of techniques, procedures and
instrumentation and are requested to report
their results with a best estimate of combined
uncertainty according to ISO I /BIPM II
guidelines3. IMEP is open to all laboratories
Figure 1
2 6
V A M
B U L L E T I N
on a voluntary basis and full confidentiality
with respect to the link between results and
identity of each participant is guaranteed.
IMEP is focused as much as possible to ‘real
life’ samples and IMEP-rounds are organised
in cases where the objective evaluation of
measurement results is important and critical.
IMEP aims at result-oriented evaluation of
the measurement capability of participating
laboratories. The European Accreditation
(EA) has recognised the characteristics of
IMEP, and as a result, IRMM now offers
IMEP as a tool to accreditation bodies.
IMEP rounds are open to all interested
laboratories world-wide, which is also
reflected in the number of participants. The
various rounds have at times several hundred
participants. IMEP also operates with
Regional Co-ordinators (RC) in various
countries. The RCs are very valuable to the
programme, since information can be
distributed and discussed at local level
without language barriers. It makes the
rounds faster in terms of logistics and in
return the various countries obtain valuable
information concerning the State of Practise
in their country through the RCs. Since
1988 IMEP rounds have mainly
concentrated on trace elements in various
matrices such as water4,5,6, polyethylene7,8,9,
I N T E R N A T I O N A L
serum10,11,12 and car catalysts13. Carbon and
oxygen isotope ratios in carbon dioxide14,15
and trace elements in sediments16 have been
successfully completed.
At present, the round IMEP-12, Trace
Elements in Water, is ongoing and
interested laboratories are welcome to
contact the IMEP office at IRMM. The
deadline for registration to IMEP-12 is
March 2001. IMEP-16, Lead in Wine, is
closed for reporting results and the round is
now in the evaluation phase. IMEP-16
had 160 participating laboratories.
Furthermore, IMEP-17, Trace and Minor
Constituents in Human Serum, is in the
planning stage. Samples are being certified
and the round will be open to interested
laboratories in the autumn 2001.
Future planned rounds are IMEP-18,
Sulfur in Oil and IMEP-19, which will
focus on a rice material.
A web site devoted entirely to IMEP has
been designed and is currently running as a
sub site at the IRMM home page (see
address below). On the new IMEP web site,
detailed information can found concerning
ongoing rounds, future rounds but also
completed rounds. All documentation can be
downloaded including various publications.
Meeting, ed. by BIPM, Sèvres, Cedex,
France (1995).
3. Guide to the Expression of Uncertainty
in Measurement, ISO, Geneva, (1995).
Uldall, M. Loikkanen, M.M. Müller, J.-C.
Libeer, H. Steensland, K. Hellsing, A.
Squirrell, L.A. Penberthy, D. Schiel, T.
Tamberg, T. Walczyk and J.W.H. Lam
(1999), Accred. Qual. Assur., 4, 463-472.
4. A. Lamberty, L. Van Nevel, J. R. Moody
and P. De Bièvre (1996), Accred. Qual.
Assur., 1, 71-82.
13. A. Held, L. Van Nevel, E. Poulsen and P.
D. P. Taylor, IMEP-11 participants
report GE/R/IM/1/99, EUR 18735 EN.
5. L. Van Nevel, P.D.P. Taylor, U.
Örnemark, J.R. Moody, K.G. Heumann
and P. De Bièvre (1998), Accred. Qual.
Assur., 3, 56-68.
14. J. V. Nørgaard, H. Kipphardt, S. Valkiers
and P. D. P. Taylor (1999), “IMEP-8:
Carbon and Oxygen Isotope ratios in
CO2 – Certification Report”, EUR 19061
EN, EC-JRC-IRMM, Geel, Belgium.
6. I. Papadakis, J.V. Nørgaard, E.
Vendelbo, L. Van Nevel and P.D.P.
Taylor, (2001), Analyst, 126, 228-233.
7. A. Lamberty, P. De Bièvre and A. Götz,
(1993) Fres. J. Anal. Chem, 345, 310-313.
8. L. Van Nevel, E. Poulsen, I. Papadakis
and P.D.P. Taylor, EC, JRC, IRMM
internal report, IMEP-10 participants
report GE/R/SIM/11/98.
9. L. Van Nevel, E. Vendelbo and P.D.P.
Taylor (2000), “The IRMM International
Measurement Evaluation Programme,
IMEP-13: Trace Elements in Polyethylene – Report to Participants”, EUR
19562 EN, EC-JRC-IRMM, Geel, Belgium.
10. P. De Bièvre, J. Savory, A. Lamberty
and G. Savory (1988), Fres. Z. Anal.
Chem, 332, 718-721.
1. I. Papadakis and P.D.P. Taylor, (2000)
Accred. Qual. Assur., 5, 331
11. A. Lamberty, J. Savory, J.R. Moody, P.
De Bièvre, K. J. R. Rosman and J. W.
Gramlich (1998), Accred. Qual. Assur, 3,
447-458.
2. Comité Consultatif pour la Quantité de
Matière (CCQM), Report of the 1st
12. U. Örnemark, L.Van Nevel, P.D.P.
Taylor, P. Robouch, P. De Bièvre, A.
REFERENCES:
N E W S
15. L. Van Nevel, E. Poulsen and P.D.P.
Taylor (1999), “IMEP-8: n(13C)/n(12C) and
n( 18 O)/n( 16 O) in CO 2 – Report to
Participants”, EUR 19060 EN, EC-JRCIRMM, Geel, Belgium.
16. I. Papadakis, E. Vendelbo, L. Van Nevel
and P.D.P. Taylor (2000), “The IRMM
International Measurement Evaluation
Programme, IMEP-14: Trace Elements in
Sediments – Report to Participants”, EUR
19595 EN, EC-JRC-IRMM, Geel, Belgium.
For further information about the IMEP
programme, please contact:
European Commission
Joint Research Centre
Institute for Reference Materials
and Measurements
Retieseweg
B-2440 GEEL
BELGIUM
Tel
+32 14 571 682 or 702
Fax
+32 14 571 865
Email imep@irmm.jrc.be
Website www.irmm.jrc.be/imep
LGC hosts a week of
international meetings
uring November LGC welcomed over
30 delegates from around the world to
a series of meetings in the United Kingdom.
The delegates were all collaborators in
CCQM activities. The CCQM (Consultative
Committee on Amount of Substance) is the
steering committee for international chemical
metrology and has recently extended its
activities to address biometrology. The
CCQM aims to resolve the practical
difficulties of achieving comparable
measurements and to provide an
international structure of national and
regional laboratories. These will demonstrate
D
the equivalence of their measurement data
through a series of key comparisons, which
reflect applications relevant to industry,
trade, health, environment, etc.
The main event of the week was a two –
day meeting of the CCQM Inorganic Working
Group, chaired by Dr Mike Sargent (LGC).
The four working groups of the CCQM are
the main routes for taking forward key
comparisons and other experimental studies.
They provide a more informal forum than the
CCQM itself (which meets annually in Paris)
and provide the scientists involved in CCQM
activities with an opportunity to discuss their
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work. It was also agreed to host a meeting of
the CCQM Electrochemical Analysis Working
Group, chaired by Dr Wolfgang Richter (PTB,
Germany). Many of the delegates attend both
working groups, so a joint session covering
topics of common interest was arranged. For
the same reason LGC also agreed to host a
meeting of the IUPAC Commission on
Isotope Specific Measurements.
Following submission of a paper by
LGC to the CCQM meeting held in April
2000, it was agreed to form an ad hoc
Biometrology Task Group. In order to
facilitate the work of the Group, LGC
I N T E R N A T I O N A L
hosted the first meeting on November 15.
The CCQM President, Robert Kaarls, and
colleagues from BIPM, DTI, IRMM,
KRISS, LGC, NIST, NMi, NRC and NPL
were able to spend a full day discussing
priorities for CCQM biometrology activities
and formulated an initial work plan which
will be undertaken this year.
R E F E R E N C E
N E W S
In view of the number of overseas
visitors, LGC also arranged a number of
events including a tour of its Teddington
facilities (in particular, the team undertaking
high accuracy analysis by mass
spectrometry) a formal dinner, and a
scientific seminar. The seminar was a
meeting on metals speciation, with several
M A T E R I A L S
CCQM speakers and delegates, as well as
LGC’s research team and collaborators from
Plymouth and De Montfort Universities,
and Birkbeck College. Dr Gerry Newman,
chairman of the AMC sub-committee on
‘High Accuracy Analysis by Mass
Spectrometry’, represented the RSC.
U P D A T E
New reference materials now available
L
GC continues to supply an
expanding range of reference materials
to assist analysts throughout the world.
Use of reference materials increases
confidence in analytical results and is a
useful tool for laboratories seeking
accreditation. A new selection of materials is
now available from LGC. Analysis of
environmental and food samples is
particularly important and the new selection
of materials reflects this (Table 1).
LGC7200 – LGC 7209 (meat species)
are particularly exciting as it is thought that
this is the first time such materials have been
produced. There have been increasing
problems with misleading descriptions of
meat samples, and meat mixtures are difficult
to detect. These materials are intended for
use as quality control standards in the
identification and determination of species,
and will also assist in method development.
LGC prepared the materials from prime cuts
and confirmed the identification with several
techniques including DNA analysis. The
samples are moist to simulate the sort of
samples usually encountered.
A processed pork material will be
available soon, certified for proximates, and
with indicative values for soya and casein.
For information on the types of
reference materials available or to order,
please contact:
The Reference Materials Team
LGC (Address on Pages 2 and 32)
Tel:
020 8943 7565
Email: rmsales@lgc.co.uk
For free advice on the use or world-wide
location of specific reference materials,
contact the VAM Helpdesk (page 2 and 32)
and ask for the ‘Reference Materials
Advisory Service (REMAS)’.
Catalogue Number
Material
Unit
Analytes
LGC1204
Dimethoate
250 mg
Purity
LGC1205
Malathion
250 mg
Purity
LGC1820
3,3’,4,4’-Tetrachlorobiphenyl
0.02 g
Purity
LGC1821
3,3’,4’4’,5-Pentachlorobiphenyl
0.02 g
Purity
LGC1822
3,3’4,4’,5,5’-Hexachlorobiphenyl
0.02 g
Purity
LGC6016
Estuary water
50 ml
Metals
LGC6113 (RM)
Soil
4 x 50 g
PCBs
LGC6114 (RM)
Harbour sediment
4 x 50 g
PCBs
LGC6181
Sewage sludge
100 g
Leachable Metals
LGC6182 (RM)
Sewage sludge
30 g
PAHs
LGC6187
River sediment
80 g
Leachable Metals
LGC6188
River sediment
30 g
PAHs
LGC7107 (RM)
Madeira cake
160 g
Proximates
LGC7151 (RM)
Processed meat
5 x 250 g
Proximates & nitrate
LGC7200 (RM)
Beef - raw
30 g
Species Authenticity
LGC7201 (RM)
Beef - cooked
30 g
As LGC7200
LGC7202 (RM)
Lamb - raw
30 g
As LGC7200
LGC7203 (RM)
Lamb - cooked
30 g
As LGC7200
LGC7204 (RM)
Pork - raw
30 g
As LGC7200
LGC7205 (RM)
Pork - cooked
30 g
As LGC7200
LGC7206 (RM)
Chicken - raw
30 g
As LGC7200
LGC7207 (RM)
Chicken - cooked
30 g
As LGC7200
LGC7208 (RM)
Turkey - raw
30 g
As LGC7200
LGC7209 (RM)
Turkey - cooked
30 g
As LGC7200
LGC7301
Butylated hydroxyanisole (BHA)
0.5 g
Purity
LGC7305
Potassium sorbate
0.5 g
Purity
Table 1: New reference materials produced by LGC.
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C H E M I C A L
N O M E N C L A T U R E
A trivial system for pharmaceutical products
Kevin Thurlow
LGC
P
eople frequently question the value of
systematic chemical nomenclature,
assuming they give it any thought at all.
However, it was slightly surprising to find
the following passage in Agatha Christie’s,
“A Caribbean Mystery”. One character tells
us the victim was poisoned with
“…what sounded like di-flor, hexagonalethylcarbenzol… The police doctor put it that
way so that nobody should know, I suppose,
what it really was. The stuff’s probably got
some quite simple nice easy name…”
Maybe nomenclators should be grateful
for any mention of their activities in a
popular novel, but it does help illustrate
some of the usual misconceptions. The
novelist worked in a dispensary in a hospital
during the First World War, so doubtless
had practical experience of the difficulty of
some chemical names. Pharmaceutical
products have a variety of names. There will
be systematic names (necessary for notifying
new chemicals), official ‘trivial’ names, and
trade names.
Systematic names give complete
structural information. Official ‘trivial’
names, like International Nonproprietary
Names (INN)1 will frequently contain some
structural information. Trade names will
probably give no structural information,
although they may allude to the expected
effects of the drug. Consider the well known
‘sedative-hypnotic’ depicted in Figure 1.
The IUPAC name for this is: 7-chloro1,3-dihydro-1-methyl-5-phenyl-1,4benzodiazepin-2-one. This describes the
structure unambiguously, and allows the
structure to be deduced rapidly. This gives
absolutely accurate information, rather than
trying to keep it secret. However, it does
have the obvious drawback that you would
not want to ask for it by that name in your
local pharmacy. It is clear that some sort of
short name is preferable for everyday use,
but this does have to be regulated. The
World Health Organisation started the INN
system in 1950 to fill this need. The idea
was to have registered ‘trivial’ names, which
would not clash with trade names or other
generic names. You really want one
authorised name. Proposed INNs are
published, allowing interested parties to raise
objections. If there are no objections, the
INNs become recommended. The INN
secretariat reviews any objections and takes
appropriate action. Roger Trigg of British
Pharmacopoeia Commission has explained
the procedure in some detail2.
INNs should be distinctive in sound and
spelling, and should not be too long. It is
useful for the name to reflect membership of
pharmacologically related groups, not
necessarily a great similarity in chemical
structure. The aim is not to give large
amounts of chemical information, or else
you might as well use the systematic name.
Anyway, it is easy to look up an INN and
find out what it is.
Figure 1, depicts diazepam(INN). The
‘-azepam’ tells the reader that it is a member of
the ‘diazepam group’, with the characteristic
‘benzodiazepine’ fused ring structure. Figure
2 shows the ‘-azepam’ structure.
R , R and R represent the various
substituents on the ‘benzodiazepine’
ring structure.
It will not be a surprise then
that flunitrazepam(INN) also has a
‘benzodiazepine’ structure, with ‘fluoro-’ and
‘nitro-’ groups attached. Similarly,
Nitrazepam(INN) has a ‘nitro-’ group.
However, although temazepam(INN) has the
characteristic structure shown in Figure 2, the
name gives no hints regarding the nature of
the other substituents. You might think this is
1
Figure 1: Diazepam.
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Figure 2: -azepam structure.
a failure of the system, but the INN
secretariat found that some prefixes were
appearing much too frequently, so they now
recommend using a neutral prefix, which
does not give too much chemical information.
The important idea is to have a short, unique,
distinctive name. Lorazepam(INN) has
‘chloro-’ groups attached. You might expect
this to be called ‘clorazepam’ or
‘chlorazepam’, but there was already a
‘clorazepate’, which also has a
‘benzodiazepine’ structure. The structural
differences are sufficient to demand a
different ending to the name. The INN
secretariat is careful not to allow names that
are too similar, particularly if they have
similar medical actions. It is essential to avoid
confusion over names, as the use of the wrong
drug could lead to the death of a patient.
Hence anything ending ‘-azepam’ will
have related medical effects. More recent
INNs do not necessarily give this much
structural information, but ‘-caines’ are local
anaesthetics, like lidocaine (formerly known
as lignocaine), and ‘-profens’ are antiinflammatory drugs, like ibuprofen. Coming
right up to date, anything ending ‘-mab’ will
be a monoclonal antibody, from the brave
new world of biotechnology.
These generic names are very useful,
particularly in the pharmaceutical industry
and in medicine. However, manufacturers are
going to want catchy trade names, to increase
sales. Diazepam’s most common proprietary
name is Valium, but there are many others.
These include Serenack, Stress-Pam,
Calmpose, Notense, Evacalm and Tensium.
It is difficult to deduce any structural
information from these names. You might
guess they are benzodiazepines, but you could
C H E M I C A L
N O M E N C L A T U R E
not be sure. However, it is fairly obvious what
the intended effect of the drug is. The
plethora of different trade names for
diazepam does highlight the problem outlined
earlier. It is quite usual for patients to
grumble that their doctor has changed a
medicine, and they hope the new drug will be
as effective. The patient may well be receiving
the same drug under a different name. The
use of a variety of trade names for the same
drug can cause confusion. Nobody will be
F O R T H C O M I N G
able to remember all of them.
So all the types of names have their uses.
The systematic name gives specific chemical
information, but might be complicated. The
INN gives general pharmacological
information, with a simplified name. The
trade name may give few clues as to the drug’s
use, but should at least be easy to pronounce.
REFERENCES
1. International Nonproprietary Names
(INN) for Pharmaceutical Substances,
Cumulative List No. 9, (1996) published
by WHO, ISBN 92 4 0560165
2. Chemical Nomenclature, edited by K J
Thurlow,
published
by
Kluwer
Academic, (1998), ISBN 0-7514-0475-6
For advice on chemical nomenclature,
contact the VAM Helpdesk (page 2 and 32)
and ask for the ‘Chemical Nom-enclature
Advisory Service (CNAS)’.
E V E N T S
Training courses at LGC
Good scientific practice
for chemical analysis
April 10–11, 2001
October 9–10, 2001
It is essential that analytical results are fit
for purpose and meet the needs of those
requesting the analysis. Implementing the six
VAM Principles is one approach towards
achieving this aim. This course is designed
for laboratory managers and senior analysts,
who are involved, or about to be involved,
with the specification of analytical
requirements and the selection of analytical
methods to meet the needs of a client. It
illustrates ways of implementing these
principles and ensuring customer satisfaction
cost-effectively.
Statistics for analytical
chemists
May 9, 2001
September 25, 2001
January 10, 2002
This one-day training course is aimed at
analytical chemists who need to use statistics
and need a better understanding of the
packages they use. The course starts from
looking at the data and explaining what the
statistical parameters that describe the data
mean, as well as how to evaluate them.
Theory is kept to a minimum but there will
be ample opportunity for practice.
Measurement Uncertainty (MU)
Principles of MU
June 6, 2001
November 13, 2001
February 5, 2002
Implementing MU principles
in chemical testing
June 7, 2001
November 14, 2001
February 6, 2002
The ability to estimate measurement
uncertainty will give you and your customers
CONFIDENCE in your results. These
courses are ideally suited to analytical chemists
who are involved in method development
and method validation. The concepts of
measurement uncertainty will be explained,
as stated in the new EURACHEM/CITAC
Guide, “Quantifying Uncertainty in
Analytical Measurement”. The lectures and
workshops will show how to calculate and
apply measurement uncertainty by step-bystep instructions and clear worked examples.
Method validation
July 3–5, 2001
December 11–13, 2001
March 5–7, 2002
Method validation is a process that
provides evidence that a given analytical
method, when correctly applied, produces
results that are fit for purpose. The course is
designed for laboratory managers and
analytical chemists, who are involved in
method development and method validation.
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It will provide an understanding of method
validation; its requirements and tools needed
to carry it out. It will also demonstrate the link
between method validation with measurement
uncertainty and equipment qualification.
ISO 17025
June 21, 2001
September 11, 2001
February 19, 2002
The standard ISO/IEC 17025: 1999:
General requirements for the competence of
testing and calibration laboratories is replacing
ISO/IEC Guide 25, M10 and EN 45001.
Accreditation bodies, such as UKAS in the
UK, are using it as the basis of their
accreditation. This course is designed to
help testing laboratories that are currently
accredited to manage the change. It also will
help laboratories, considering accreditation,
to plan their activities.
These courses can be customised to
suit an individual company’s needs
and delivered in-house, if six or
more staff require training.
Further information is available from
both the VAM and LGC’s websites
(page 2 & 32) or by contacting:
Lorraine Didinal,
LGC (Address on Pages 2 and 32),
Tel:
020 8943 7631,
Fax:
020 8943 2767,
Email: lad@lgc.co.uk.
On-line registration is also
available on the VAM web site.
A D V E R T I S E M E N T
“YOUR GATEWAY TO RELIABLE RESULTS”
Launch of the new VAM web site
By the time this edition of the VAM Bulletin
goes to print, initial work should have been
completed and the new VAM web site
launched. This new site provides a vital
source of information for anyone interested
in valid analytical measurements. The site
has been considerably updated with a
wealth of new information and a new easy
to use navigation system. Check out the
site for yourself at www.vam.org.uk and
register as a VAM member on-line (free of
charge): to access even more information.
Listed below is just some of the
functionality and content you will discover
when you enter this new gateway to
reliable results.
About VAM
News
❖ find out more about VAM
❖ learn how to implement the
❖
❖
❖
❖
VAM Principles
❖ check out the technical projects
being undertaken
read the latest VAM Bulletin on-line
read the latest news
review the Bulletin and news archive
check out forthcoming events
Communities
Advice & Information
❖ give your views on one of the
❖ ask a question and seek
bulletin boards
technical advice
❖ find out the latest from any clubs
❖ review frequently asked
or networks you belong to
questions (FAQs)
❖ find help on a particular topic
❖ use the interactive guidance on buying
analytical services & selecting
laboratories
Training & Education
Publications
❖ search the library of reports, papers,
❖ find a suitable training course
or seminar
books and audio visual aids
❖ download many reports & papers
for free
❖ order books and other
❖ make an on-line booking
❖ get guidance on laboratory skills
and competencies
products on-line
❖ obtain training & teaching resources
❖ enter PT competitions for schools
❖ check out the latest events for
universities, colleges & schools
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F O R T H C O M I N G
E V E N T S
Other events
National measurement
conference – BEMC 2001
November 6–8, 2001
Majestic Hotel, Harrogate
This conference is a 3-day parallel
meeting devoted to advances in
measurement technology and research
practices within the UK. Workshops and
seminars will be run during the conference
to address common issues. Alongside
technical sessions there will be an exhibition
of measurement providers, instrument
suppliers and accredited calibrated
laboratories.
Those interested in presenting a
paper at the conference may, in the first
instance, submit an abstract of not more
than 200 words.
Further information is available from:
Hannah Edmunds
National Physical Laboratory
(Address on back cover)
Tel:
020 8943 6260
Email: hannah.edmunds@npl.co.uk
Web:
www.nmpuk.co.uk
C O N T A C T S
Contact points
For advice on:
For information and advice on:
•
•
•
•
•
• Gas analysis;
• ‘Availability of Gases Awareness Club’
Analytical quality assurance;
Chemical nomenclature;
Proficiency testing;
Reference materials;
Statistics.
Contact:
Paul Holland
Environmental Standards Group
Centre for Environmental and Optical Metrology
NPL
Tel:
020 8943 7174
Email: paul.holland@npl.co.uk
Contact the VAM Helpdesk
Tel:
020 8943 7393
Email:
vam@lgc.co.uk
Web site: www.vam.org.uk
LGC
Queens Road
TEDDINGTON
Middlesex, TW11 0LY
Tel: 020 8943 7000 (switchboard)
Fax: 020 8943 2767
Web: www.lgc.co.uk
National Physical Laboratory (NPL)
Queens Road
TEDDINGTON
Middlesex, TW11 0LW
Tel: 020 8977 3222 (switchboard)
020 8943 6880 (NPL Helpline)
Fax: 020 8943 2155
Web: www.npl.co.uk
Aerosol Science Centre
AEA Technology plc
E6 Culham, ABINGDON
Oxfordshire, OX14 3DB
Tel: 01235 463677
Fax: 01235 463205
Email: aerosols@aeat.co.uk
Produced by Horrex Davis Design Associates 3/01
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