Swollen polysiloxanes as stationary phases in reversed-phase open-tubular column liquid chromatography

Abstract

A new liquid stationary phase was created after swelling cross-linked polysiloxanes with non-polar organic solvents in 11–55 μm I.D. fused-silica open-tubular columns. By choosing different polysiloxane/swelling solvent pairs, the stationary phase film thickness, retention and selectivity could be adjusted within a wide range. Using n-heptane as the swelling solvent, the film thickness increased by a factor of 3–4. Mobile to stationary phase volume ratios, β  V m/ V s, down to 2 were obtained. An increase in retention of 12–16 times after swelling was observed. Improved stability was obtained as compared with conventional liquid—liquid chromatographic systems with mechanically held stationary phases. The system was stable at very high flow-rates (up to 6.3 cm/s) and showed no mechanical loss of the stationary phase.