Royal Society of Chemistry
Mastership in Chemical Analysis (MChemA)
Examiners report 2015
Mr Shayne Dyer (Chief Examiner)
Mr Jon Griffin
Ms Jane White
Dr Mike Foulkes
Introduction
This is the annual report of the Examiners for the Mastership in Chemical Analysis for the
year ending 31 December 2015. These general comments are intended for candidates and
their counsellors, to help them understand the expectations of the examiners and to aid their
preparations for the MChemA.
The MChemA Regulations, Syllabus and Guidance Notes can be found on the RSC website
at www.rsc.org/mchema
Part A (14 April 2015, Burlington House)
Two candidates, A and B, sat the exam. Both candidates passed with marks of 47% and
53%, respectively. The two candidates answered the same three out of their five questions
attempted, ie questions 1, 5 and 6. The two candidates displayed similar ‘marks’ profiles in
these three questions, as well as in their two individual questions (questions 7 and 8 for
candidate A and questions 2 and 4 for candidate B) indicating some similarities in depth of
knowledge and understanding. Candidate A managed to pass three out of the five questions
while candidate B passed four out of the five questions.
Question 1 (define and discuss five analytical terms and nomenclature) was answered by
both candidates and both attempted all five parts. However, only two or three of the five
parts were in each case presented in any depth resulting in similar marks for this question
within a spread of ~48 – 55%.
Question 2, a ‘practical’ question requiring an understanding of GC and how data from GCFID instrumentation can be manipulated was attempted by only one candidate. Three of the
four parts of this question were attempted, including the graphical treatment section,
producing a sound answer with a mark of 65%. This type of question was introduced some
three years ago to allow candidates to demonstrate their practical data handling abilities
given the raw data output from an instrumental technique commonly encountered in the PA
laboratory. The use of linear range-response to calculate the original concentration of an
unsaturated fatty acid in an “olive oil” sample curiously presented quite a challenge in terms
of the final fourth section of this question.
Neither candidate answered Q3 which focussed on direct solids analysis using x-ray
diffraction and x-ray fluorescence techniques. This question, which was in four sections,
required an explanation of how the instruments worked and with diagrams to explain the
theory and practical layout of the instruments. This question also asked the candidates to
consider the chemometric-statistical analysis of data from instruments together with an
appraisal of statistical confidence and possible bias.
Question 4 asked for four out of the six liquid chromatography systems presented, to be
discussed in terms of their specific underlying analytical principle and details of the various
mobile and stationary phases employed in their use. Candidate B attempted this question.
Examples of sample types and analytes were expected in each case. Two of the four
analytical systems were provided with suitable details while two were in brief form only,
resulting in just a pass.
Question 5 was attempted by both, and asked candidates to discuss and evaluate the
possible interferences associated with, and limitations of, five commonly encountered
instrumental techniques used in laboratories. An understanding of the origins of these
interferences and where these techniques can ‘trip you up’ is important. Candidates were
given ‘free rein’ as to examples / conditions to use, in order to demonstrate this detailed
practical knowledge. Unfortunately, this question proved to be quite a challenge and in both
candidate cases only limited relevant detail was provided and not all five parts were
attempted, resulting in a low marks spread of 15 to 23%.
Question 6 was in a number of ways the saviour question for the candidates. Six dissolution
techniques were presented, as used in analytical laboratories and candidates were asked to
describe the principles behind and application of four of these. Suitable examples of sample
types, reagents and apparatus used and a relevant analyte of interest were required in the
answer for each technique. Very good detail, with relevant examples and conditions were
provided by both candidates for this practical-type question, resulting in marks within the 80
– 85% range.
Question 7 was introduced to allow the candidates to demonstrate their knowledge and
understanding of biochemical techniques, as used within the public analysts laboratory these
days. To some extent, the question was presented in an open format requiring any two
biochemical analytical techniques of their choice to be discussed (e.g. Immunoassay,
Aptamer, ELISA, DNA and PCR techniques etc.) in terms of their importance, biochemical
principle upon which they are based, the advantages gained by their use and a suitable
analyte and sample type presented to demonstrate its application. Only one candidate
attempted this question and only one technique was actually discussed in the analytical
sense with only some details provided; hence the lower mark score of 30%.
Question 8 was answered by just one candidate. This question asked for a discussion of the
key practical steps involved, with details, in acquiring a measure of the level of “dichlorvos”,
an organophosphate pesticide, from a sprayed crop in a 10 hectare field. Details to consider
in the analytical steps included, taking suitably representative samples, their collection,
storage and preparation, their extraction, pesticide measurement, its evaluation and required
validation procedures. The integrity of the sample was also to be noted. Various relevant
sections were provided by the candidate, some in more depth than others and some were
quite well handled. However, some expected critical information was not provided and as a
result a mark of around 60% was given for this question.
Other comments for both candidates
• “A picture paints a thousand words!” i.e. include well annotated diagrams, where
appropriate, since this can be a much more effective way of illustrating something than
pages of text.
• Be sure to address the question asked and not to be drawn into discussing a related topic
simply because you know more about it or are especially familiar with it from your own
work experience. Examiners will only award marks for information that is relevant.
• Where possible, address all that is asked in the question and answer ALL parts of the
question.
Part B (13-14 October 2015 Burlington House)
One candidate presented for the Part B examination and was successful in only Paper 1.
The following comments relate to the examiners expectations of the papers rather than to
the performance of the candidate.
Paper 1
Question 1
Detail the current legislation which is applicable to the assessment of heavy metals in food.
It was expected that the candidates would refer to The Contaminants in Food Regulations
2103 as the enabling regulations and to Commission Regulation 1881/2006 and also to
333/2007 (sampling in analysis). The answers should include the metals covered by the
regulations, details of the sampling requirements, sample preparation and performance
criteria for the methods used. (16 Marks)
The second part of the question required candidates to identify the limitations of the
legislation. Limitations include product types not covered and compound foods. (4 Marks)
Question 2
Discuss the methods available for quantifying allergens in food.
It was expected that the candidates would briefly describe the methods available (Elisa,
DNA, Shiptons for SO2) and give an indication of their benefits and shortcomings (10 marks)
Second part - Outline the requirements of the Food Information Regulations with regard to
Allergens. It was expected the candidate to give a list of the allergens, labelling requirements
and exemptions (6 marks)
Third part
Discuss the significance of four allergens at given levels. It was expected that
candidate would be able to briefly layout their interpretation of the results. (4marks)
Question 3
Outline the analysis necessary to assess the authenticity of 5 food stuffs out of six.
Some of the food types given had compositions prescribed in legislation Honey, Marmalade,
milk chocolate and plain flour. It was expected that the candidate would be able to identify
the correct legislation and therefore the appropriate tests. Two food stuffs are not covered by
legislation Dairy Ice-cream and Marzipan. The composition of dairy ice-cream was covered
by the Food Labelling Regulation and it was expected that the candidate would use this as a
reference source. Marzipan is a traditional product made from ground almonds and therefore
the analysis selected should be directed to the presence of almonds and other nuts. (20
marks)
Question 4
Discuss the main requirements of the Food Supplement (England) Regulations 2003.
With good knowledge of the legislation this question on main requirements of the Food
Supplements Regulations should be straight forward (10)
The second part of the question required assessment of nutritional claims on two food
supplements and an outline of the method of analysis used. The answer should reference
the Nutrition and Health claim legislation with an indication of the level required to fulfil the
claim. (10 marks)
Question 5
What factors would determine the shelf life of vacuum packed smoked fish (6 marks).
The shelf-life of food products is dependent on the interactive effects of intrinsic parameters
such as. pH, water activity and preservatives) and extrinsic parameters like. storage
temperature and gaseous environment, as well as the raw material quality and sanitary
conditions applied during manufacturing.
Detail the analysis/examination you would perform to assess the shelf life (14 marks)
A number of variables must be considered when designing a shelf-life study. Storage
temperature, relative humidity, types of analyses (i.e. microbiological, chemical or
organoleptic analyses), method of analyses, sampling method, number of replications and
duration of the study are some of these variables.
Question 6
Outline the main provisions of the current food additive legislation. (16 marks)
The Food Additive Regulations are encountered by Public Analysts on a regular basis.
Commission Regulation 1333/2008 is constantly being updated so a good knowledge is
essential. The structure of food additive legislation has changed. In the past the regulations
have been based on the individual additive. The present legislation focuses on the food type
and therefore is more complex
The second part of the question asked for the definition of three terms. (4 marks)
Question 7
The first part of the question required the definition of 6 DNA terms (6 marks)
DNA analysis has become one of the most important techniques used in laboratories. A
good knowledge of the terms used is therefore essential.
The second part of the question required discussion of DNA extraction (14 Marks)
Candidates with actual experience of DNA extraction techniques would have an advantage.
A public analyst must also recognise the problems that are encountered during DNA
analysis and how to correctly interpret the results obtained
Question 8
Explain the significance of 5 organisms with regard to ready to eat food. Including in the
answer microbiological criteria and indicating satisfactory and unsatisfactory results (20
marks)
It would be expected that the candidate would have knowledge of the effects and severity of
any poisoning resulting from the named organisms.
Paper 2
Question 1
Explain what pressures can and have impacted on food production in the world and how this
could affect food safety and adulteration. (20 marks)
Candidates who have kept themselves informed of global food problems should have no
difficulty in answering this question. Examples such as the crop failures (almonds and
spices), natural disasters (tsunami in Japan) and criminal activity (horse meat scandal) could
be given and the resulting outcomes explained.
Question 2
Discuss the primary legislation relating to food law and how this is implemented with respect
to controlling imported food. (20 marks)
It is expected the candidate would refer to the Food Safety Act 1990, The Official Feed and
Food Controls Regulation 2009, EC Regulation 882/2004 and EC Regulation 669/2009.
Question 3
Discuss the main provisions of regulation EC 767/2009 on placing on the market and use of
animal feeding stuffs. (20 marks)
With a good knowledge of the regulations this question should not have presented any
problems.
Question 4
First part of the question required the definition of the nutritional significance of 5
components (10 marks)
Second part required how each component would be analysed components. (10 marks)
With a good knowledge of feeding stuffs and analysis
presented any problems.
this question should not have
Question 5
In terms of plant nutrition discuss the significance of primary, secondary and trace elements.
Give examples how they affect plant growth and crop production.
With a good knowledge of the plant nutrition this question should not have presented any
problems.
Question 6
The first part of the question required the definition of five terms associated with the
sampling of animal feeding stuffs (10 marks)
The second part required discussion of the methods of mycotoxins in feeds and
interpretation of the results. (10 marks)
With a good knowledge of the legislation this question should not have presented any
problems
Question 7
Describe the requirements of the Private Water Supply Regulations 2009. (20 marks)
It was expected that the general requirements of these regulations would be explained and
the difference between these regulations and the Water Supply regulations 2010 identified
(such risk assessment and sampling requirements)
Question 8
This question required the candidate to describe the analysis and interpretation of four water
contaminants.
The given contaminants, with the exclusion of the indicator organisms, require fairly complex
analysis and they may not be encountered in every Public Analyst laboratory. However it
would be expected for a candidate to have a good working knowledge of their analysis and
the interpretation of the results.
Part C (9th September 2015 Reading University)
Two candidates presented for the part C paper. Both candidates were sitting the paper for
the first time. Neither candidate passed all three sections as required.
The candidates were presented with the three certificate questions, the three microscopy
questions and the two interactive questions when the exam started at 9am. One of the
interactive questions relating to animal illness required the candidates to contact trading
standards before 10:30 to obtain additional information. Additional material in the form of
forage was available when requested.
Part C requires good time management. .It is an advantage if the candidate can practise
working to tight time constraints
Section 1: communication in the form of formal certificates
The examiners do not prescribe a particular approach to the production of a certificate. The
main requirement for a certificate is that they are acceptable to a court of law. They should
show identify the relevant legislation (if any), include all pertinent information and a have
positive statement of the offence or opinion. .
Question 1
This question related to the interpretation of the result of analysis for a minced beef and the
supplied label (10 marks)
The Food Information Regulations 2014 brought specific compositional and labelling
requirements for minced beef. To interpret the provided results further calculations are
required. This would show a high collagen/meat protein ratio. The provided labelled did not
bear the required statements and the nutritional declaration was incorrect.
Question 2
This related to a fish sauce contaminated with heavy metals and histamine.(10 marks)
The uncertainty of measurement has to be applied to the given analytical value which would
show a lead level which would fail legislation.
The level for histamine in fish sauce was issued in an amendment to EC regulation
2013/2005 on 23 October 2013. The level of histamine in the sauce would fail the
regulations.
Question 3
This was a question to check the awareness of the tolerances applied to fertiliser
declarations and the correct naming of the product. (10 marks)
In this case, the product is an NPK Fertiliser solution which is in Schedule 1, Section C,
Group 2 of the Fertilisers Regulations 1991.
The declarations indicate that the nutrients NPK are above their minimums (2,3 and 3%
respectively) and the total is not less than 15%
On analysis, the total N content is within the LOV of 1.1%. The P content is also within its
LOV of 1.1% but the K declaration is below 3.5% and so the tolerance is in column 6 of the
schedule and not column 5 (schedule 1 (6)) so P2O5 satisfactory and so K2O low and
outside the LOV.
The total (N+P+K) is above 15% so can be called an NPK Fertiliser solution.
The Ureic N content is outside the tolerance of 1.5% and so low ((schedule 1 (7b)).
N+P+K total negative deviation is 1.9% which is OK.
Ureic N correctly included in the statutory statement.
Microscopy and Identification.
When performing microscopy a systematic process must be followed. The examiners can
award marks if candidates draw and label what they have seen even if they cannot make a
positive identification. The presence or absence of a structure can enable a candidate to
include or exclude a plant structure. If this is detailed in the candidates’ notes then additional
marks may be awarded.
The number of marks allocated to each question indicated to the candidate the complexity of
the sample.
This year the microscopy examinations were not well documented with a lack of diagrams.
This is most probably due to the candidates running out of time
Question 4
Spice mix for roast vegetable.(16 marks)
This was a quaternary mixture of paprika, turmeric, cinnamon and rock salt. The salt was
easily visible by spreading the sample out and viewing with a hand lens. The other
components are common spices and should have been reasonably easy to identify.
Question 4
Unknown mixture from a health food shop. (9 marks)
This sample consisted of a mixture of tea and senna leaf. Visually the sample could be seen
to consist of two different coloured components enabling an initial separation.
Whilst senna leaf is not often encountered it does possess distinctive structures. A high mark
could still be achieved even if a correct identification was not obtained provided there were
good labelled diagrams.
Question 5
Fibre (5 marks)
Jute fibres in flour
The examiners would expect a candidate to follow one of the documented procedures for
fibre identification. A systematic approach would yield the correct identification.
Problem Solving – Interactives
Question 7
The candidates were informed that a takeaway has been opened by an Indian who has
recently come to the United Kingdom. The takeaway owner stated that he only uses
traditional ingredients (20 marks)
The sample consisted of a beef curry. No point of sale information was available. It was
requested that the sample was tested for compliance with current legislation.
The sample contained water buffalo meat, sunset yellow, mustard oil and ghee.
This interactive is fairly opened ended as far as the type of analysis requested is concerned.
The candidates took this on board and requested appropriate analysis which reflected
current legislation and know current food problems.
Candidates can make use of the internet. It was hoped that they would use the internet to
investigate Indian curry recipe and with that knowledge develop a plan of analysis.
The candidates correctly identified the presence of an incorrect meat species. However the
only methods requested were based on Elisa techniques. Elisa tests would only give a slight
positive reaction to beef. Whilst this would be sufficient to show that the meat present was
not beef it does not identify the actual meat used. For this DNA identification must be used.
The legislation for colours changed in 2013 such that sunset yellow was no longer permitted
in curry sauces. This was identified by the candidates following request for general colour
analysis.
At the interviews in the afternoon the candidates were encourage to look at the wording of
the question more closely as it was apparent from the requested analysis that they had
missed the “clues” about traditional ingredients and the owner recently coming to this
country. After the interviews some more relevant analytical requests were made.
Question 8
“Mr A Jones. Trading Standards Officer would like to speak to you about a complaint from a
local farm where illness has been reported in some livestock. Please could you contact him
before 10:30 as he will be unavailable after this until the afternoon”. (20 marks)
A feeding stuff was provided at the start of the exam.
Contacting the Trading Standards officer would supply additional information on the illness
provided the correct questions were asked.
Such questions could include:1 Which animals were affected – in this case sheep
2 Symptoms
3 How quickly the illness came on
4 Any changes in the animals’ environment. – Sheep now grazing on pasture after flooding.
The assumption was made by the candidates that there was a fault with the feeding stuff
either compositionally or through the presence of excess copper. Analysis of the feeding
stuff showed no problems.
The second part of the sample, the forage, was provided in the afternoon as a prompt to
consider additional analysis.
Since sheep are low grazing animals and can crop plants close to the root they are
susceptible to consuming environmental contaminants. If the forage had been tested for
contaminants such as heavy metals, PCBs and dioxins it would have shown high levels of
PCBs and dioxin like PCBS. The soil in the pasture had been contaminated during the flood.
It has become apparent over the past few years that candidates are supplying the examiners
with fully documented methods. It is a concern of the examiners that if a candidate does not
have a documented method then feel they can’t request an analysis. This is not the case;
the examiners will accept a brief outline of the requested method. Candidates must also
recognise that if they require analysis of an extracted component of a food, such as fat, then
the method for extracting that component must also be submitted.
Thanks
The examiners would like to thank Dr Alex Kersting and her colleagues at the Royal Society
of Chemistry for their support and proficient administration of the process.
Mr Chris
Humphreys at the Food Biosciences Department in Reading for his enthusiastic help in the
part C examination.
,