What is a chromatographic column and what is its function

The Chemistry Dictionary tells you what a chromatography column is and what it does. A chromatographic column is a tube packed with a stationary phase to separate mixed components. It consists of column tube, pressure cap, ferrule (sealing ring), sieve plate (filter disc), joints, screws, etc. So what is a chromatography column?

What is a chromatographic column

The chromatographic column consists of column tube, pressure cap, ferrule (seal ring), sieve plate (filter), joints, screws, etc. Column tubes are mostly made of stainless steel. When the pressure is not higher than 70 kg/cm2, thick-walled glass or quartz tubes can also be used. The inner wall of the tube is required to have a high smoothness. In order to improve the column efficiency and reduce the tube wall effect, the inner wall of the stainless steel column is mostly polished. Some people also apply fluoroplastic on the inner wall of stainless steel columns to improve the smoothness of the inner wall. The effect is the same as polishing. There are also those using fused silica or glass liners for thin tube columns. The column joints at both ends of the chromatographic column are equipped with sieve plates, which are sintered stainless steel or titanium alloy with a pore size of 0.2~20μm (5~10&μm), depending on the particle size of the filler, in order to prevent the leakage of the filler.

The role of chromatographic columns

Chromatographic columns can be divided into analytical and preparative types according to their uses. The dimensions and specifications are also different: ① Conventional analytical columns (constant columns), inner diameter 2~5mm (commonly 4.6mm, 4mm and 5mm in China), column length 10~30cm ; ② Narrow bore (also called narrow bore, semi-microcolumn), inner diameter 1~2mm, column length 10~20cm; ③ Capillary column (also called microcolumn), inner diameter 0.2~0.5 mm; ④ semi-preparative column, inner diameter >5mm; ⑤ laboratory preparation column, inner diameter 20~40mm, column length 10~30cm; ⑥ production preparation column inner diameter can reach tens of centimeters. The inner diameter of the column is generally determined based on the column length, packing particle size and reduced flow rate in order to avoid tube wall effects.