GC-MS – Gas Chromatography-Mass Spectrometry
The gas chromatography with mass spectrometry coupling is used for the separation, identification and quantification of organic compounds or mixtures of substances.
The method is based on the evaporation of a substance with subsequent injection into a gas chromatographic system. Due to their physical-chemical properties, the components have different characteristic flow rates, which results in a separation. During the following ionization (by EI-electron-ionization, CI-chemical-ionization or FI-field-ionization), it comes to a partial fragmentation and protonation of the separated substances. The final detection is done after separation of the charged ions (into their mass-to-charge ratio) by electric or magnetic fields.
From the detected mass numbers of the mole peak (CI), characteristic fragments (EI), and potential isotopic patterns, the structure and molecular formula of individual compounds can be calculated.
With the GC-MS also very complex mixtures of substances can be separated. Due to the principle of operation, all vaporizable substances with relatively low molecular mass (mass of approx. < 1000 u) are suitable for the method.