STUDY OF THE RESPONSE OF 3 LIQUID-CRYSTALS AS STATIONARY PHASES FOR THE GAS-CHROMATOGRAPHY OF SOME CYCLIC MONOTERPENE VOLATILE OIL CONSTITUENTS WITH SHORT RETENTION TIMES

Eight cyclic monoterpene volatile oil constituents of short retention time were studied using three liquid crystals as gas chromatographic stationary phases in packed columns. Two phases (below) exhibited a different solute elution sequence after melting and supercooling. The third, bis-(methoxy-benzylidineanil-chloroaniline), did not, but still showed fairly good resolution. However, azoxydiphenetole offered the identification advantage of considerable changes in solute relative retention times, with melted vs. unmelted ratios of x 1.5 to x 3.0. Cineole and terpinolene were distinctive in giving for this ratio only x 0.9 on bis-(methoxy-benzylidineanil-bitoluidine). The results suggest that various parts of the melted or unmelted liquid crystal molecules participate in retaining the various solutes.