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Methods of chromatography
In IB chemistry curriculum, you should know that:
- Chromatogram – a visible record showing the results of separation of the components of a mixture by chromatography
- Rf value is unit used to compare how far a component has travelled up a TLC plate in relation to the solvent front
Rf = distance moved by component ÷ distance moved by solvent front
- Retention time – the time for a component to pass from the column inlet to the detector,
in gas chromatography - In GC the area under each peak is proportional to the amount of a compound in the sample.
GC-MS
GC-MS (gas chromatography and mass spectrometry) is a combined analysing tool; GC is used to separate components in a mixture and MS is used to identify components by comparing them to a database.
Applications of GC-MS in IB chemistry:
- Forensics – identify substance at a crime scene, which can be used as evidence in a court of law
- Environmental analysis – monitoring and analysing organic pollutants, quality of waste and drinking water; and detecting pesticides in food
- Airport security – detect explosives in luggage and on people to prevent terrorist attacks and identify substance to prevent drug trafficking
- Space probes – analyse atmosphere of planets and materials on their surface
- Drugs – detect the presence of illegal drugs or performance enhancers in suspected drug users and athletes
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Drafted by Gina (Chemistry)