GC057 Advantages of Capillary Columns

 They are open tubes; hence the pressure drop through them is small. Long lengths, such as 60 m can be easily used. In classical packed columns, the material is tightly packed and, therefore, producing greater pressure drops. This fact also limits packed columns lengths, which is around 2 m. This difference makes capillary columns more efficient in terms of resolution. The capillary columns have typical efficiencies of 3000-5000 theoretical plates per meter. On the other hand, efficiencies in packed columns are around 2000 plates per meter, due to thicker and nonuniform films. Thus, total plates available in long capillary columns is huge compared with packed columns, resulting in greater resolutions.

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