Developments in polysiloxane stationary phases in gas chromatography

Abstract

Summary Although the requirements of stationary phases have continued to become more stringent with the development of instrumental techniques the polysiloxanes have remained as the major group of stationary phases. While the early industrial polysiloxane products have long been replaced by refined specially products, development has continued with the preparation of polysiloxanes specifically for gas chromatography and particularly capillary gas chromatography. The efficiency of polar capillary columns has been low but recent advances with immobilized phases have been most promising. The acknowledged thermal stability of the polysiloxane backbone has been employed in several ways. Such as with chiral pendant groups to facilitate the separation of optically active materials and with mesogenic groups to provide phases with superior properties to the low-molecular-weight liquid-crystal materials. Further modification of the polysiloxanes has been achieved by the inclusion of other metallic atoms. The most important development in recent years is the introduction of bonded or immobilized phases. Extensive studies have allowed the production of efficient polar capillary columns which are now commercially available.