The second-hand liquid mass spectrometry instrument adopts liquid mass spectrometry technology, also known as liquid chromatography mass spectrometry technology, which uses liquid chromatography as a separation system and mass spectrometry as a detection system. The sample is separated from the mobile phase in the mass spectrum part, and after ionization, the ion fragments are separated by mass number by the mass analyzer of the mass spectrum, and the mass spectrum is obtained by the detector. Each component of the sample separated by liquid chromatography enters the mass spectrometry detector in turn, and each component is ionized at the ion source to produce ions with a certain charge and different mass numbers. The motion behavior of different ions in the electromagnetic field is different. The ions are separated according to the mass charge ratio by mass analyzer, and the mass spectrum arranged according to the mass charge ratio is obtained. The qualitative and quantitative results of the sample can be obtained by analyzing and processing the mass spectrum. It is mainly used in drug metabolism and pharmacokinetic research, clinical pharmacology research, natural medicine (Chinese herbal medicine, etc.) development research, newborn screening, protein and peptide identification, residue analysis, toxicological analysis, environmental analysis, environmental protection, food, tap water, health and epidemic prevention and other industries.

On-line combination combines the separation power of chromatography with the qualitative function of mass spectrometry to achieve more accurate quantitative and qualitative analysis of complex mixtures. It also simplifies the sample pretreatment process and makes the sample analysis easier. Chromatographic mass spectrometry includes gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS), and liquid mass spectrometry is complementary to temperament spectrometry to analyze compounds with different properties.

The mass spectrometry process can be divided into four basic steps:

1. The sample is introduced and vaporized through a suitable sampling device;

2, the sample after gasification is introduced into the ion source for ionization, that is, the ionization process;

3, the ionized ions after proper acceleration into the mass analyzer, according to different mass-charge ratio for separation;

4. After detection and recording, a spectrum diagram was obtained.