Gas Chromatography-Mass Spectrometry (GCMS)

AMI uses a Varian 450-GC and 220-MS.

GCMS combines two analytical techniques: gas chromatography and mass spectrometry. The gas chromatography portion is used to separate volatile or semi-volatile components in a mixture. A liquid sample is vaporized and carried through the column with a carrier gas. As the vaporized compounds are pushed through the column, they slow down when they interact with the stationary phase. Different chemicals will take longer or shorter times to reach the end of the column based on their chemical properties. As the chemicals are separated, they are transferred to the mass spectrometer.

Once in the mass spectrometer, the compounds are ionized causing them to break into fragments--many with a positive charge. The pattern of resulting fragments acts as a highly specific “fingerprint” that can be used to identify the chemical. Our MS is an ion trap, so the ions are confined within a single region and time-dependent electromagnetic fields eject them in order of increasing mass-to-charge (m/z) ratio. After ejection, the ions are measured by the detector. The recorded data at each point in time of an experiment is called a mass spectrum, and can be used as the "fingerprint" to identify the chemical.

Typical methods include: