Effect of film thickness and supercooling on the performance of cholesteryl cinnamate liquid crystal capillary columns

Abstract

SummaryImproved separations of the isomers of olefinic aliphatic insect pheromones were obtained on cholesteryl cinnamate glass capillary columns by operating in the supercooled temperature range of the liquid crystal. Capillary columns were prepared with varying film thickness of the stationary phase; choice of the correct film thickness ensured optimum retention for a wide range of compounds within the most effective temperature range of the liquid crystal. The deactivation procedures described made the liquid crystal columns suitable for separation of the geometric isomers of polar and nonpolar compounds.

Current aspects of the stationary phase in gas chromatography

“…To utilize the advantages of liquid crystals, they should be applied to capillary columns. The three different types of mesophases were thus applied to capillary columns by Sojak et al [138-1421; cholesteryl cinnamate liquid crystals [143,144] and high temperature liquid crystals have also been applied [145]. In those cases where the liquid crystals are poor film builders, high column efficiencies might be obtained if they are applied in a matrix of silicone gum [146-1481.…”

Determination of the minimum allowable operating temperature of stationary phases in capillary columns by inverse gas chromatography

“…Similarly, thermal transitions of liquid crystalline phases resulted in a discontinuity in the curves retention time vs. reciprocal temperature. 38,39 However, not every thermal transition may be observed. 39 (ii) The film thickness influences the T g of a polymer and, therefore, its MiAOT.…”