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 capilla ry column supercritical fluid chromatography (SFC). Silica particles w ere deactivated with 50% cyanopropyl-substituted polymethylhydrosiloxa ne, and coated with 25% o,p-dicyano-p-biphenyl-substituted polymethyls iloxane (o,p,p-DCBP), and 25% m,m-dicyano-p-phenyl-substituted polymet hylsiloxane (m,m,p-DCBP) stationary phases. Argentation of the particl es was carried out by complex formation between silver ions and the cy ano groups on the particles. Unsaturated fatty acid methylesters (FAME s) were used to investigate the selectivity of these packing materials to double bonds using packed capillary column SFC. Separations were p erformed according to the degree, position, and geometrical configurat ion of the double bonds. The effect of temperature on selectivity was also investigated. The stability of the packing materials was evaluate d by monitoring the loss in selectivity of the oleate/elaidate isomers after washing the column with supercritical CO2 at 300 atm and 85 deg rees C. The separation of FAMEs in a commercial fish oil was compared using capillary columns packed with DCBP coated and silver-complexed p articles. (C) 1995 John Wiley & Sons, Inc.