Gas Chromatograph Mass Spectrometer (GC MS Instrument)

Gas chromatograph mass spectrometers (GC MS) are to volatile chemical compounds what liquid chromatography (LC) MS systems are to materials in solution: they separate and analyze gas-phase molecules. In LC, compounds are fractionated based on their differential affinity for the separation’s mobile (liquid) and stationary phases (column packing material). In GC, heated, volatile compounds are injected into a flowing gas stream and separated as that stream flows through a long hollow tube (sometimes tens of meters in length) coated with a stationary phase material. In GC MS, the fractionated compounds are then ionized (typically by electron ionization) and injected into the mass spec analyzer, most commonly a single quadrupole (though triple quadrupoles and time-of-flight analyzers are also available). Gas chromatograph mass spectrometers are generally used to analyze small, relatively non-polar compounds, and are widely used in forensics, food safety, environmental monitoring, and petrochemicals, among others.