A column is a major component of a Gas Chromatograph in which the separation of sample components takes place. As compared to the packed ones capillary options are always better. A Capillary GC Columns is a very popular type. It comes with a stationary phase which is coated on the inner surface and columns are preferred over the packed variants. For a chromatography process, the columns require a smaller amount of sample. The size of the column comes with a diameter.