Abstract Heretofore, experience accumulated during the past two years on the utilization of fused-silica glass for the fabrication of capillary columns for gas chromatography has revealed certain advantages and disadvantages associated with this unique material. Surfaces relatively free of metal oxides, when appropriately coated with certain stationary phases provided excellent columns that were thermally stable and well deactivated. However, it was also noted that the precise chemical nature of the fused-silica glass surface, after drawing at 2100°C, was more complex than anticipated. This was reflected by our inability to coat columns with either very non-polar liquids, i.e. squalane, Apiezon L, C 87 hydrocarbon (Kováts) or the highly polar stationay phases (the cyanopropyl silicones). By carefully surmising the nature of certain of the reactions that may occur on the surface of this glass under different conditions, one is able to utilize this information to extend the number of stationary phases that can be coated on fused-silica glass capillary columns. Accordingly, it has been shown that the selective chemical bonding of the surface layer of the fused silica prior to specific coating provides one with flexibility and versatility in the successful application of many different liquid phases.