Chromatography, also known as chromatography or chromatography, is a physical and chemical analysis method. It uses the difference of force (distribution, adsorption, ion exchange, etc. ) between different solutes (samples) and stationary and mobile phases. When the two phases move relatively, each solute is balanced between the two phases for many times, so that each solute is separated from each other.
When making ink painting, the painter will coat the pigment (ink) on the paper, and use the gradual fading of the color when the pigment is spread on the paper to obtain the effect of color transition. This actually involves the application of chromatographic principles. Among them, the paper is the stationary phase, the pigment is the mobile phase, and the gradual separation of water and dye in the pigment forms the transition color.
Using the principle of chromatography, different components in flowing objects can be separated (regardless of color at this time). Some specific substances (such as alumina) are put into a test tube and sent from one end to the mobile animals (mobile phase) that need to be separated. Because of the different forces between different components and fillers in flowing animals, the time for different components to come out from the other end will be different. According to the components flowing out at different times, we can know the components of flowing animals (chromatographic analysis), or extract the components flowing out at a specific time to get high-purity substances (chromatographic extraction). Here, the tube filled with a specific substance is called a chromatographic column (not necessarily a column in practical application, but also a coil), and the process of loading a specific substance is to load a column.
When filling chromatographic column, if the filling is not tight and uniform, the mobile phase and stationary phase (filler) will act unevenly, which will lead to the anxiety that the same component will flow out first and then affect the separation or extraction. Therefore, uniformity and compactness can improve the separation efficiency of spectral columns; Blocking with absorbent cotton can prevent the stationary phase (filler, alumina) from loosening, and pressing with absorbent cotton can prevent the pressing surface from forming an excessively tight layer.