The hexamethylene alkyl benzene liquid crystal monomers are used in the Thin Film Transistor (TFT) liquid crystal
the first grade tiny Twisted Nematic (TN) and the Super Twisted Nematic (STN). The impurity affects resistivity
clearing points and the low temperature property of the mix liquid crystal a lot. In this work
the different polar gas chromatographic column and reversed-phase liquid chromatographic column are used to separate the cis-trans production to find the best column and the optimal analytical method. GC-MS is also used to determine the cis-product qualitatively.