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A chromatograph is based on the principles of chromatography, which is a separation technique. The separation of a sample mixture involves the continuous distribution of its various components between two phases within what is known as a chromatographic column. A chromatograph can conduct a comprehensive analysis of the sample being tested; it can identify the various components in a mixture as well as determine the concentration of each component. Therefore, chromatographs are widely used in scientific experiments and industrial production. Principle of operation of chromatographic analyzers: The separation of mixtures is the key aspect of chromatography; this separation process is a physicochemical process that is carried out by the chromatography column. The sample to be separated is carried continuously through the chromatography column by a gas or liquid; this gas or liquid that carries the sample is known as the mobile phase. The chromatography column contains solid particles or liquids coated on a support; these do not exert any physicochemical effect on the mobile phase, but they can absorb or dissolve the various components in the sample being analyzed, and they have different capacities for absorbing or dissolving different components. Solid particles or liquids in a chromatography column that do not move with the mobile phase are collectively referred to as the stationary phase. Chromatography makes use of the fact that the stationary phase in a chromatographic column has different absorption or solubility properties for the various components in the sample to be analyzed. These components are repeatedly distributed between two phases, which allows them to be separated; as a result, they emerge from the chromatographic column in a specific order. A detector is installed at the outlet of the chromatography column; when a component flows from the column into the detector, the detector outputs an electrical signal corresponding to the concentration of that component. By recording the output signals corresponding to each component with a recorder, a chromatogram is formed, as shown in Figure 1. The composition of the mixture and the concentration of each component can be determined based on the time at which they appear in the chromatogram and the size of their peaks. Explanation of the detection principle of the chromatograph: 1 represents the carrier gas ； 2 is the sample ； 3 is the chromatography column ； 4 is the detector ； 5 refers to the chromatogram. Figure 1 shows the process of separating the mixture in the chromatography column. Since the mobile phase can be either gas or liquid, and the stationary phase can be either liquid or solid, chromatography is divided into types such as gas-liquid chromatography, gas-solid chromatography, liquid-liquid chromatography, and liquid-solid chromatography. Regardless of the chromatography method used, the basic principle remains similar. Source: Technical Library http://yunrun.com.cn/tech/