苯甲酸在对叔丁基杯[4]-1,2-冠4固定相上的保留机理

Retention mechanism of benzoic acid on p-tert-butyl-calix[4]arene-1,2-crown-4 stationary phase

选用自制的对叔丁基杯[4]-1,2-冠-4(Cx4-4)键合固定相,通过改变流动相中甲醇比例和pH值,考察了苯甲酸(BAH)在Cx4-4键合固定相上的保留行为。采用量子化学计算方法中密度泛函理论(DFT)中的B3LYP/STO-3G*基组对建立的Cx4-4与BAH相互作用的超分子构型进行了优化和频率计算,得到了超分子相互作用的稳定化能和吉布斯自由能;根据计算结果对BAH在杯芳烃固定相上的保留机理进行了研究,并进一步建立了食品中BAH在Cx4-4色谱柱上的高效液相色谱(HPLC)分离分析方法。

The chromatographic behaviors of benzoic acid（BAH） were investigated on a self-made p-tert-butyl-calix[4]arene-1,2-crown-4（Cx4-4） stationary phase by changing methanol content and pH value of the mobile phase.The results show that hydrophobic interaction is the main interaction in the separation of benzoic acid,moreover,inclusion interaction,π-π and hydrogen bonding interactions also play additional roles.A Density Functional Theory（DFT） method with the base set of B3LYP/STO-3G＊ was employed to explain the interaction between BAH and Cx4-4,and the optimized supramolecular structure（Cx4-4 and BAH）,the Gibbs free energy change（ΔG） and stabilization energy change（ΔE） were obtained.With the assistance of quantum chemistry calculation,the separation mechanism is further discussed.The quantum chemical calculation results were consistent with the retention behavior of BAH on Cx4-4 stationary phase.Finally,by using the self-made Cx4-4 column,a high performance liquid chromatographic（HPLC） method for the analysis of BAH in tuber mustard and vinegar was developed.