# A sports scientist collects a urine sample from an athlete and sends it to a laboratory for analysis. The laboratory uses gas chromatography (GC) linked to mass spectrometry (MS) to test whether the sample contains any banned performance-enhancing substances. Explain how GC-MS allows the laboratory to identify any banned substances present in the urine sample.

> Edexcel A-Level Chemistry (9CH0) — Topic 6 Modern analytical techniques · Explain · 5 marks

## Mark scheme (5 marks)

1. Gas chromatography separates the mixture into its individual components
2. Different components travel through the GC column at different speeds / take different amounts of time to pass through
3. Each separated component then enters the mass spectrometer
4. The mass spectrometer produces a fragmentation pattern / mass spectrum for each component
5. The mass spectrum is compared to a database / library of known substances to identify the component

## Key terms

- [gas chromatography](https://www.gradenine.co.uk/glossary/gas-chromatography)
- [mass spectrometry](https://www.gradenine.co.uk/glossary/mass-spectrometry)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-sports-scientist-collects-a-urine-ca237c92) · Published by Druglandscape Ltd.