Gas Chromatography–Mass Spectrometry (GC-MS)

GC-MS is a combination of gas chromatography and mass spectrometry in which the separation ability of gas chromatography is used along with the identification power of mass spectrometry. It is one of the most popular analytical methods for samples consisting of volatile or semi-volatile compounds (liquid, gaseous, or solid). GC-MS systems are useful for determining the identity and the amount of components in a mixture of unknown composition.
GC-MS can only analyze those samples that can be injected into the GC. Typically, these are volatile substances (essential oils from plants with low boiling points) or substances that can be converted into volatile substances by derivatization. In the system, the mixture components are first separated in a GC column. After the carrier gas has been removed, the analytes are drawn into the ionization source of the mass spectrometer, where high-energy electric fields fragment and identify them based on their mass-to-charge ratios.
A major plus point for this method is its speed: components can be identified in less than 90 seconds after entering the system. GC-MS is also extraordinarily sensitive – down to the picogram range – so it is possible to determine the exact composition of complex samples with extraordinary accuracy.