Use and maintenance of liquid chromatography column

The liquid chromatograph consists of three parts: high pressure liquid pump, detector and liquid chromatography column The correct installation and use of the liquid chromatography column is the key to the work of liquid chromatography, and it is also the only way for the liquid chromatography workers to obtain correct and reliable experimental data I installation of liquid chromatographic column: 1 Structure of liquid chromatographic column: a the empty column is composed of column joint, column tube and filter piece The column joint adopts a low dead volume structure The column joint is a threaded component at both ends, with 7 / 16 inch external thread at one end and 3 / 16 inch internal thread at the other end (standardized at home and abroad) 7 / 16 "external thread is connected with 1 / 4" column pipe (Φ 6.35mm), and the middle part is placed for sealing The 3 / 16 inch internal thread is connected with the 1 / 16 inch (Φ 1.57mm) connecting pipe, and a compression ring is also placed in the middle to seal the column joint In order to minimize the dead volume outside the column, when installing the chromatographic column, insert the Φ 1.57mm connecting pipe through the hollow screw compression ring as far as possible, and then tighten the hollow screw After the compression ring is squeezed and deformed by the hollow screw, it is tightly clamped on the connecting pipe (the length of the pipe exposed after the connecting pipe passes through the compression ring shall be strictly controlled within 2.5mm or other fixed dimensions) In the column joints at both ends, a stainless steel filter (or filter screen) shall be placed at both ends of the column to block the packing of the column from being washed out of the column by the mobile phase All components of the air column are made of 316 × stainless steel, which can withstand general solvent action However, the solvent containing chloride has certain corrosiveness to it, so it should be noted that such solvent cannot be kept in the column and connecting pipe for a long time to avoid corrosion B column packing: the separation of the liquid chromatographic column is carried out between the packing and the mobile phase, and the classification of the column depends on the type of packing Normal phase column: mostly silica gel as the column filler According to the shape, it can be divided into two types: amorphous and spherical The particle diameter is in the range of 3-10 μ M Another kind of normal phase packing is the surface bonding of silica gel - CN, - NH2 and other functional groups, which are called bonded phase silica gel Reversed phase column: it is a kind of nonpolar packing mainly based on silica gel and bonded with Octadecyl functional group (ODS) on its surface There are also no stereotypes and ball type Other commonly used reversed phase fillers include bonded C8, C4, C2, phenyl, etc., with particle size between 3-10 μ M.