High performance liquid chromatograph (HPLC) is an instrument based on the principle of high performance liquid chromatography, which is mainly used to analyze less-volatile and thermal-unstable organic compounds with high boiling point and large molecular weight. It consists of reservoir, pump, sample injector, chromatographic column, detector and recorder. The mobile phase in the reservoir is pumped into the system by a high-pressure pump, and the sample solution passes through a sample injector then enters the mobile phase, which loads the sample solution into a chromatographic column (stationary phase). Because the various components in the sample solution have different distribution coefficients in the two phases, when they are moving relatively in the two phases, after repeated adsorption-desorption distribution processes, the moving speed of each component is greatly different, and the components are separated into single components flowing out of the column in turn. When passing through the detector, the sample concentration is converted into electrical signal and transmitted to the recorder, and the data is printed out in the form of chromatogram.