5种多糖类手性柱分离19种手性多氯联苯的对比研究

Comparison of Enantioseparations of 19 Chiral Polychlorinated Biphenyls by 5 Different Polysaccharides Chiral Columns

采用高效液相色谱在正相条件下对常温稳定存在的19种手性多氯联苯（Polychlorinated biphenyls,PCBs）进行了拆分,对比了5种不同多糖类手性色谱柱的拆分效果。其中Lux Cellulose-1,Cellulose-3和Cellulose-4分离效果较好,在Cellulose-1上PCBs91,136,139,149和171可基线分离,在Cellulose-3上PCBs45,84,88,95,131,135,144和149能够完全分离,在Cellulose-4上PCBs88,131,139,171和174能够完全分离,在以上3种色谱柱上PCBs132,175,176,183,196和197可部分分离,但Cellulose-2和Amylose-2对这19种手性PCBs分离效果很差。考察了温度对拆分的影响,结果在5℃~30℃之间,PCBs对映体在Cellulose-1和Cellulose-3上对应的范特霍夫方程线性关系较好,而Cellulose-4受柱温影响不稳定。手性PCBs拆分过程整体受焓驱动,温度降低有利于对映体分离。利用在线旋光确定了各PCBs的对映体洗脱顺序,结果表明PCBs对映体的拆分程度和旋光洗脱顺序受苯环上氯原子取代数目和取代位置的影响。

In this study, 19 stable chiral polychlorinated biphenyls （PCBs） were stereoselectively separated on five different chiral columns packed with polysaccharides derivatives, using normal-phase high performance liquid chromatography. Satisfactory separations were obtained on Lux Cellulose-1, Cellulose-3 and Cellulose-4 column, while Cellulose-2 and Amylose-2 column showed very poor enantioselective discriminability for these chiral PCBs. PCBs 91, 136, 139, 149, 171 and PCBs 45, 84, 88, 95, 131, 135, 144, 149 could be baseline separated on Cellulose-1 and Cellulose-3, respectively. PCBs 88, 131, 139, 171 and 174 could be thoroughly resolved on Cellulose-4. However, PCBs 132, 175, 176, 183, 196 and 197 were partially separated on these three columns. In the range of 5~C -30~C, the plots of natural logarithms of the selectivity factors （lnct） versus the inverse of temperature （1/T） were linear on Cellulose-1 and Cellulose-3, but it was not linear on Cellulose-4. The separations of chiral PCBs were driven by enthalpy, meaning that low temperature was advantageous to separation. In addition, the enantiomeric elution orders of PCBs were confirmed with an online optical rotation detector. The enantioseparation and elution orders were associated with the number and position of chlorine substituted in the benzene ring of chrial PCBs. This work will be very helpful to prepare and analyze single enantiomers of chiral PCBs.