Evaluation of shape selectivity of liquid crystals in capillary gas chromatography

Abstract The shape selectivity of 4-octoxyphenyl 4-pentoxybenzoate as a liquid crystal stationary phase was monitored in the separations of o -, m - and p -xylene and cis - and trans -1,2-dimethylcyclohexane and -decalin in the temperature range 54–83°C with both increasing and decreasing column temperatures in 5°C steps. Retention indices were used to study the dependence of retention on temperature. The influence of temperature on the shape selectivity of the liquid crystal stationary phase was measured as the dependence of log α on 1/ T . The use of saturated cyclic compounds for measuring the shape-selective properties of a liquid crystal stationary phase is superior to the use of xylenes as they are less polar than xylenes and their selectivity factors are more sensitive to selectivity changes.