SOL-GEL-DERIVED FLUORINATED STATIONARY-PHASE FOR OPEN-TUBULAR ELECTROCHROMATOGRAPHY

We report on the preparation of a sol-gel-derived fluorinated stationa ry phase using a 13 mu m I.D. fused-silica capillary for open tubular electrochromatography (OTEC). The sol-gel-derived fluorinated column i s prepared by hydrolyzing a mixture of tetraethoxysilane (TEOS) and ca fluoro-1,1,2,2-tetrahydroocryl-1-triethoxysilane (F-13-TEOS) followed by coating a thin film onto the inner walls of a fused-silica capillar y. The retention characteristics of the sol-gel-derived fluorinated co lumn are compared with a sol-gel-derived octylhydrocarbonstceous (C-8) column. Using the sol-gel-derived fluorinated column, we report on th e successful separation of six model fluorinated organic compounds whi ch cannot be separated using the C-8 column prepared either via sol-ge l method or by conventional methods. We achieved high efficiencies of 100 000-300 000 plates/m for the various model fluorinated compounds u sing the sol-gel-derived fluorinated column. We have also investigated the separation performance of the sol-gel-derived fluorinated column using different TEOS:F-13-TEOS ratios and the optimum reaction time be fore column coating. Optimum selectivity was obtained with a TEOS:F-13 -TEOS molar ratio of 1:2 reacted for 24 h prior to column coating.