SILVER-COMPLEXED DICYANOBIPHENYL-SUBSTITUTED POLYMETHYLSILOXANE ENCAPSULATED PARTICLES FOR PACKED CAPILLARY COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY

High nitrile content cyano-substituted polymethylsiloxane encapsulated particles were prepared for double bond selectivity in packed capillary column supercritical fluid chromatography (SFC). Silica particles were deactivated with 50% cyanopropyl-substituted polymethylhydrosiloxane, and coated with 25% o,p-dicyano-p-biphenyl-substituted polymethylsiloxane (o,p,p-DCBP), and 25% m,m-dicyano-p-phenyl-substituted polymethylsiloxane (m,m,p-DCBP) stationary phases. Argentation of the particles was carried out by complex formation between silver ions and the cyano groups on the particles. Unsaturated fatty acid methylesters (FAMEs) were used to investigate the selectivity of these packing materials to double bonds using packed capillary column SFC. Separations were performed according to the degree, position, and geometrical configuration of the double bonds. The effect of temperature on selectivity was also investigated. The stability of the packing materials was evaluated by monitoring the loss in selectivity of the oleate/elaidate isomers after washing the column with supercritical CO2 at 300 atm and 85 degrees C. The separation of FAMEs in a commercial fish oil was compared using capillary columns packed with DCBP coated and silver-complexed particles. (C) 1995 John Wiley & Sons, Inc.