This research involved the study of the gas chrornatographic behavior of various columns packed with liquid crystal compounds as stationary phases. The studied liquid crystal compounds are 4-(pmethylbenzylid9ne) aminoazobenzene, 4-(p- methoxybenzylidene)aminoazobenzene, 4- (p-chlorobenzylidene)aminoazobenzene and the mixture of the last two with a mixing ratio of 70 / 30, respectively. These compounds have been prepared in high yield using a well known method. They have been further identified using l.R. and mass spectrometry. The phase transition temperatures ranges of these compounds have been measured using differential scanning calorimetry ( D S C ) and hot stage microscope. These compounds are characterized of having wide nematic transition temperature range. Several chromatographic columns were packed with different coating percentages (10%, 15% and 20%) of each liquid crystal compounds as well as a mixture of them on chromos orb W. A W, DMCS (60-80 mesh) . Mixture of normal aliphatic alcohols (C2-C7) and aromatic hydrocarbons (Benzene, Toluene, mixed Xylene isomers and Mesitylene ) were analyzed on each column. The best chromatographic conditions (such as column type, coating percentages and operating temperature) for the separation of the above samples were identified by measuring the resolution and selectivity factors for the
separated sample components, it has been found that best chrormatographic performance can be achieved with columns coated with 15% liquid crystal stationary phase at operating temperature at which nematic mesophase start to form. All prepared columns have shown good separation capabilities, especially the column 4-(p-methoxybenzylidene)aminoazobenzene, which has demonstrated excellent chrormnatographic performance for all sample mixtures.