Basic separation principle and overview of liquid chromatography
There are two phases in the chromatogram, one phase is immobile, we call it the stationary phase, and the other phase flows through the stationary phase, which we call the mobile phase. The principle of separation of chromatography is to separate the various substances to be separated in the two phases, such as the partition coefficient, adsorption capacity and the like. An external force is used to pass the mobile phase (gas, liquid) containing the sample through a surface of the stationary phase that is fixed in the column or on the plate and is incompatible with the flow. As the mixture carried in the mobile phase flows through the stationary phase, the components of the mixture interact with the stationary phase. Due to the difference in properties and structure of the components in the mixture, the magnitude and strength of the force generated between the stationary phase and the stationary phase are different. As the mobile phase moves, the mixture undergoes repeated distribution and balance between the two phases, The components are retained by the stationary phase for a different period of time, thereby flowing out of the stationary phase in a certain order. In combination with an appropriate post-column detection method, the separation and detection of each component in the mixture are achieved.
Liquid Chromatography Overview
Among all chromatographic techniques, liquid chromatography (LC) was first developed (1903), but its initial development was slow. Before liquid chromatography, paper chromatography, gas chromatography and thin-layer chromatography The method is the mainstream of chromatographic methods. In the late 1960s, the theory and technology of gas chromatography, which had been developed more maturely, was applied to liquid chromatography, which led to the rapid development of liquid chromatography. In particular, the preparation technology of the filler, the detection technology and the continuous improvement of the performance of the high-pressure infusion pump have made the liquid chromatography analysis efficient and high-speed. A liquid chromatograph with these excellent properties was commercialized in 1969. Since then, this liquid chromatography with high separation efficiency and fast analysis speed is called high performance liquid chromatography (HPLC), also called high pressure liquid chromatography or high performance liquid chromatography.