Gas chromatograph - mass spectrometer, referred to as GC-MS in English. It is widely used in environmental protection industry, electronics industry, textile industry, petrochemical industry, flavor and fragrance industry, pharmaceutical industry, agriculture and food safety fields etc. to Carry out the analysis of organic pollutants in the environment, analysis of pesticide residues, animal residues, and drug residues, analysis of aroma components of flavors and fragrances, and detection of harmful substances in the textile industry. So, how does it work?
I. The working method of gas chromatography (GC)
Analysis principle: Each component in the sample is separated between the mobile phase and the stationary phase due to the different distribution coefficients.
Representation method of the spectrum: the change of the post-column effluent concentration with the retention value
Information provided: The peak retention value is related to the component thermodynamic parameters, which is a qualitative basis, and the peak area is related to the component content.
II. The working method of mass spectrometer (MS)
Analysis principle: Molecules are bombarded by electrons in a vacuum to form ions, which are separated by electromagnetic field according to different m/e.
Representation method of the spectrum: indicate the change of ion relative kurtosis with m/e in the form of a bar graph
Information provided: the mass numbers and relative kurtosis of molecular ions and fragment ions, providing information on molecular weight, element composition and structure.
In simple words, a gas chromatograph - mass spectrometer is an integrated device of a gas chromatograph and a mass spectrometer, which is a precise analytical instrument for detecting and qualitatively and quantitatively analyzing compounds. The gas chromatograph makes the vaporized sample enter into the chromatographic column for separation, and the separated compound enters the mass spectrometer for detection. The obtained material chromatogram and mass spectrogram are compared with the library file to know the composition of the compound more accurately.