New method for the preparation of highly stable polysiloxane-coated glass open-tubular capillary columns and application to the analysis of hormonal steroids.

A new approach to the preparation of methylsiloxane-coated glass open-tubular capillary columns is described. A siloxane polymeric mixture is first prepared by hydrolysis of dimethyldichlorosilane. The polymer is then coated on to the previously etched glass wall by a base-catalyzed reaction to yield a non-polar system of high stability and showing satisfactory chromatographic properties. This type of column has been used for the high-resolution separations of complex hormonal steroid mixtures. The flexibility of this method should permit the preparation of capillary systems with a wide range of polarity.