Gas chromatography - mass spectrometry (GC-MS)

Gas chromatography (GC)

Gas chromatography is used to separate the analytes to be investigated. The chromatography column consists of a 15 to 100 m long glass capillary which is flooded with an inert gas such as helium. The evaporated analytes are injected into the stream of gas and travel through the column based on their physical and chemical properties. This way, very complex analyte mixtures can be separated into their components.

Mass spectrometry (MS)

Mass spectrometry is used to identify and quantify the separated substances. In the mass spectrometer, the components are ionized by electron impact ionization (EI) which leads to their fragmentation. From the mass numbers of the mol peak and of characteristic fragments, and from the isotope pattern (if present), the chemical formula can be determined.

Figure 1: Schematic representation of a GC-MS.