USE OF A LIQUID-CRYSTAL STATIONARY PHASE AT TEMPERATURES BELOW ITS MELTING-POINT FOR THE GAS-CHROMATOGRAPHIC STUDY OF SOME VOLATILE OIL CONSTITUENTS

The liquid crystal bismethoxybenzilidine-bitoluidine (BMBT), used as the stationary phase for the gas chromatographic study of some aromatics and a monoterpenoid constituent of volatile oils, gave best results used below its melting point of about 180-degrees-C. At these temperatures (120-175-degrees-C), relative retention times to linalol were dependent on whether the column was heated from ambient conditions, or cooled from above the melting point. Changes in the sequence of retentions (terpineol-estragole and anethole-thymol " shifts") suggested this liquid crystal may operate by three different mechanisms, dependent on the column treatment. Results are given for fennel and tea-tree oils.