CYANOBIPHENYL-SUBSTITUTED POLYMETHYLSILOXANE ENCAPSULATED PARTICLES FOR PACKED CAPILLARY COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY

Nine isomeric cyanobiphenyl-substituted (25%) polymethylsiloxane (CBP) stationary phases were coated and immobilized by free-radical crosslinking on silica packing materials for use in supercritical fluid chromatography (SFC). The selectivities of these packing materials to benzene derivatives, polycyclic aromatic hydrocarbons (PAHs), and double bonds in fatty acid methylesters (FAMEs) were determined. Among the nine isomeric CBP-coated packing materials, the o, p-CBP phase was found to be the most selective to both double bonds and aromatic isomers under SFC conditions. The durability of the packing; materials was evaluated by measuring the changes in selectivity with SFC use. The loss iri selectivity was less than 0.20% after being continuously washed by supercritical carbon dioxide at 100 degrees C and 300 atm for more than 100 h. (C) 1995 John Wiley & Sons, Inc.