Types of HPLC columns
Classification of chromatographic columnsThe chromatographic column (separation column) of HPLC is one of the most important components, which can be generally divided into three types: reversed phase column, normal phase column and other columns.
① Reversed phase chromatographic column: it is the most commonly used chromatographic column; generally, it accounts for about 70%; among them, C18 column accounts for 65%; C8 column accounts for about 15%; phenyl column is less than 5%. Reversed phase chromatography (RP-HPLC) is one of the most widely used high performance liquid chromatography (HPLC). C18 is most widely used in reversed phase chromatography. Probably more than half.
② Normal chromatographic column: the normal chromatographic column is also often used, which accounts for about 20%.
③ Other chromatographic columns (chiral column, ion exchange column): about 10%.
The use and protection of chromogenic column is a problem that needs special attention. If it is slightly careless, it may reduce the column efficiency, shorten the life of chromatographic column, and even damage the chromatographic column. The key points of using chromogenic column are introduced below.
The key to using a chromotropic column.
① Wash the column frequently. After each use, it must be washed with strong solvent for about 30 minutes, or about 20 times of the volume of the washing bed (column volume).
② When the chromatographic column is not used for a long time, the chromatographic column should be filled with methanol or acetonitrile, and finally immersed in methanol; the author generally immerses the chromatographic column that has not been used for a long time in methanol, and the effect is very good.
③ The column head must be tightened and no buffer should be left in the column.
④ When changing the composition of solvent, the switching between organic solvent and water should be carried out slowly. If the change is fast, the column may be damaged.
⑤ For the sample of complex system (such as biological sample, traditional Chinese medicine sample) must be pretreated, or a protective column should be added between the chromatographic column and the injector.
⑥ The general chromatographic column cannot be backwashed, otherwise the column efficiency will be reduced rapidly; however, the column manufacturer indicates that the column can be backwashed.
⑦ The chromatographic column should not be subjected to strong mechanical vibration; it should not be used in the case of rapid changes in pressure and temperature, otherwise the packing in the column will be affected.
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