COLUMN PACKINGS WITH IMMOBILIZED METHYL POLYSILOXANE PHASES FOR GAS-CHROMATOGRAPHY

The free radical cross-linking procedure of stationary phase immobilization introduced by Grob et al. for capillary columns has been adapted for the preparation of column packings on diatomaceous supports. Immobilization of SE-30 and OV-1 on typical gas chromatography supports: Polsorb B-AW, Chromosorb W-AW, Chromosorb G-AW and Gas Chrom Q was investigated. Before immobilization, the supports (excluding Gas Chrom Q) were purified by extraction with 6 M HCl in a Soxhlet extractor and silanized with hexamethyldisilazane vapour at 300-degrees-C. The influence of the type and concentration of peroxide on the efficiency of immobilization of the silicone was studied. In order to obtain over 95% immobilization a minimum of 2 % w/w of the peroxide in the stationary liquid is required. Properties of packings with immobilized phase were compared with those of related conventional packings. Adsorption activity, column efficiency and thermal stability were used for this comparison.