Preparation of glass capillary columns coated with polar phase for hogh-temperature gas chromatography. 1. Study of Roughening of the glass surface

Some methods of surface roughening of glass capillary columns have been studied (viz., HCl etching, controlled devitrification and deposition of fine particles). The reaction of HCl with soda-lime glass proceeds easily, but is a self-limiting process. The resultant NaCl initially forms globules, which become cubic after prolonged heating. The presence of excess of HCl (as in flowing methods) or water reduces the crystallization rate markedly. A method of surface crystallization based on controlled devitrification has been developed. Spiked surfaces are obtained, which can easily be deactivated by current methods. The deposition of fine particles on the column wall offers another approach. A method is described for the preparation and application of (sub)micron NaCl particles, which results in a surface comparable with an HCl-etched surface. Preliminary results are given for surface-roughened capillary columns at high temperatures coated with polar phases.