Improvements in the performance of etched glass capillary columns

Abstract

The surface of hydrogen chloride etched, glass capillary columns can be rendered less active by heating at 400°C for 3 hours in a stream of dry nitrogen prior to coating. The reduction of surface activity is probably caused by loss of water from surface silanol groups to produce siloxide bridges. In addition, such treatment almost halves the bleed rate of columns coated with OV 101 silicone oil stationary phase at 280°C and causes no deterioration in the wetting properties of the etched glass surface.