What Is a Gas Chromatograph Mass Spectrometer?

Gas chromatography-mass spectrometer refers to an instrument that combines the high-performance separation capability of a gas chromatograph with the unique selectivity, sensitivity, relative molecular mass, and molecular structure identification capabilities of a mass spectrometer. The principle is that the multi-component mixture is gasified and separated by gas chromatography. Each component enters the mass spectrometer in order according to the retention time. The gas molecules of each component are ionized in the ion source to generate positively charged compounds with different mass-to-charge ratios. The ions are formed into an ion beam by the acceleration of the electric field. After entering the mass analyzer, the ions are separated according to the mass-to-charge ratio. Finally, the detector detects the electrical signals converted by the ion beam current and is sent to the computer. After processing, chromatograms, mass spectra, and other information can be obtained. The molecular ion peak, isotope peak, and characteristic fragment ion peak of the mass spectrum of a component are related to the molecular structure of the component. By comparing with the standard mass spectral library, the component can be characterized and its structure determined. The concentration of a component is directly proportional to the ion current intensity of the base peak in its mass spectrum, and the component can be quantitatively analyzed. ^[1]