INSTRUMENTATION SUMMARY
Instrument
Mass Spec
Principles
Positively charged
ions are separated
according to
different relative
masses when
moving through
magnetic field
Instrument
Atomic Absorption
Spectrometer
Principles
Ground state atoms
of an element
absorb light
characteristic of that
element.
Processes
Vapourisation
Ionisation
Acceleration
Separation
Detection
Processes
Dissolve sample
Atomise (spray
sample solution into
flame & sample is
converted to atoms
of element )
Absorption is
Absorb (Ground
directly proportional state atoms absorb
to concentration.
radiation from
source made from
(higher absorbance
same element)
means higher
Measure the
concentration of
absorbance by
THAT ELEMENT
Detecting amount of
present)
light
Uses
Measure Mr
Analyse organic
pollutants in water
Analyse blood of
race horses for
doping
Uses
Detect and measure
heavy metals in
water.
Cadmium Lead
Instrument
Gas
ChromatographyGC
Principles
Different
components have
different tendencies
to dissolve in a nonvolatile liquid, which
is coated on fine
particles of a solid in
a the GC column
Processes
Injection
Transport of sample
along column
Separation in column
Detection
Instrument
HPLC
High performance
Liquid
Chromatography
Principles
Different
components of a
mixture have
different tendencies
to adsorb onto fine
particles of solid in
HPLC column
Processes
Injection
Transport of sample
along column
Separation in column
Detection
Uses
Blood alcohol
test
Drug tests for
athletes
Analyse growth
promoters in
meat or vitamins
in food
Instrument
IR
Infra red
spectrometry
Principles
Molecules of a
substance absorb
infra –red of
different frequencies.
The combination of
frequencies absorbed
is peculiar to the
molecules of each
substance
Processes
Prepare sample
Transmit :
IR radiation passes
through sample
Sample absorbs IR
radiation at specific
wavelengths which
are detected
Absorption
spectrum obtained
Instrument
UV
Ultra violet
spectrometry
Principles
Molecules absorb
UV radiation
Electrons promoted
from ground state to
higher energy states.
Absorption is
directly proportional
to concentration.
Processes
Prepare sample
Principles
Wavelengths of
Xrays are
comparable to
distance between
atoms in a crystal
Xrays are scattered
when they hit a
crystal surface
Pattern detected is
analysed and
structure worked out
Processes
Prepare crystal
OPTION 2
Instrument
X-ray
crystallography
Transmit :UV light
is passed through
sample and a blank
Absorption
spectrum obtained
Transmit :
Narrow beam of xray of particular
wavelength directed
at crystal
Reflected x-rays
detected on film
Pattern analysed and
structure worked out
Identifying diff
subs. e.g. plastics
or drugs
Quantitative
technique used in
quantitative
determination of
drug metabolites
and plant
pigments.
DNA structure
(Dorothy
Hodgkin)
Vitamin B12
(Bragg and
Bragg)