Abstract: p-Dodecaoxydithiobenzoic acid-nickel(Ⅱ) complex with a liquid crystal nature(DDBN) was synthesized and characterized by using the differential scanning calorimetry(DSC) and GC. DSCmeasurements showed that DDBNexhibited a mesomorphic behavior and that the phase transition occurred at 95 ℃ and 125 ℃. The dependence of lg k'vs. reciprocal temperature for cycloparaffins indicated also the same temperature of phase transition. In this paper, DDBNwas used first as the stationary phase to the separation of positional isomers. The results indicated that DDBNwas stable at temperature ranging from 80 ℃ to 240 ℃ and adequate for the separation of isomer of polycyclic aromatic hydrocarbon. 1-Methylnaphthalene and 2-methyl-naphthalene were separated at the baseline using₃ m×3 mm column of DDBN. Phenanthrene and anthracene were separated also easy using the same column. The infinite-dilution partial molar enthalpy and entropy of four analytes in this system were obtained by means of plotting. Thermodynamic properties and the mechanism for retention were also discussed.

Key words: Liquid crystal type stationary phase, p-Dodecaoxydithiobenzoic acid-nickel(Ⅱ) complex, Polycyclic aromatic hydrocarbon