What are the types of capillary columns?
What are the types of thin tube chromatographic columns? According to xianji.com, capillary columns are generally divided into four types: wcot, scot, clot and plot. These four types of capillary columns are briefly introduced below.The classic capillary column is wcot (wall coated open tubular column). After pretreatment, the stationary liquid is directly coated on the inner wall. Because of its difficult preparation, poor repeatability, small internal surface, small amount of coating and large relative β value, the number of effective trays and actual separation capacity are not high, and the thermal stability is poor, so it has been rarely used.
Plot porous layer open tubular column: only one layer of porous adsorbent particles is coated on the inner wall, which is a capillary gas-solid chromatographic column.
Clot cross linked open tubular column: coated with stationary solution, cross linked open tubular column is crosslinked and bonded with coupling agent. The performance of the column is greatly improved. It can resist high temperature, water and solvent.
Scot supported coated open tubular column: a layer of support coated open tubular column is coated on the inner wall of the column, and then the carrier is coated with fixed liquid. The fixed liquid membrane can be thicker and the column capacity is larger. It must be noted that the carrier in the above two columns is only coated on the wall of the capillary column, rather than filling the whole column.
Among them, plot column is mainly used for the separation of permanent gas and low molecular weight organic compounds; Scot column uses a larger amount of stationary liquid, so the column capacity is larger, but due to the complex preparation technology, the application is not very common. Clot is the main force in capillary GC. Most of its column materials are fused quartz, which is called elastic quartz column.
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