GC-MS is the short form for gas chromatography mass spectrometry. It is used for samples that are thermally stable molecules. GC-MS is also the preferred machine to use because it is easier to operate, has fewer maintenance issues, and costs less compared to the LC-MS machine.

LC-MS is the abbreviated form of liquid chromatography mass spectrometry. The technique is often applied to processes that require a high sensitivity and selectivity of the materials being identified. It is often used to make a specific detection of materials in a combined state. LC-MS can be used for non-volatile and thermally fragile molecules. The technique can be utilized to separate a wide variety of organic compounds from metabolites to proteins.

GC-MS/MS uses volatile analyte identification with low level quantitation. in this the MS column consists of two scanning mass analyzers separated by a collision cell.  Fragments selected in the first analyzer are reacted with an inert gas in the collision cell, resulting in further fragmentation.

Gas chromatography mass spectroscopy (GC/MS) is an instrumental technique, comprising a gas chromatography (GC) coupled to a mass spectrometer (MS), by which complex mixtures of chemicals may be separated, identified and quantified