Zakaria Philip, Macka Miroslav, Fritz James S, Haddad Paul R
Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia.
Electrophoresis. 2002 Sep;23(17):2821-32. doi: 10.1002/1522-2683(200209)23:17<2821::AID-ELPS2821>3.0.CO;2-L.
The separation of a series of aromatic carboxylic acids, sulfonates and opiates using electrokinetic chromatography employing a mixture of the soluble cationic polymer poly(diallydimethylammonium chloride) (PDDAC) and the amphiphilic anion hexanesulfonate as pseudostationary phases is described. In this system, the PDDAC pseudostationary phase interacts with the anionic analytes, whereas the hexanesulfonate pseudostationary phase interacts with the cationic analytes. A migration model has been derived which takes into account the ion-exchange (IE) interactions between the anions and the cationic PDDAC as well as the ion-pair (IP) interactions between the opiates and the hexanesulfonate. A further interaction between the combined PDDAC-hexanesulfonate complex and the more hydrophobic analytes is also evident and is accounted for in the model. Constants obtained by applying the model agreed well with the expected trends in IE affinities of the anions for PDDAC and also corresponded with the hydrophobic natures of the analytes. Optimization of the PDDAC and hexanesulfonate concentrations was performed using the normalized resolution product and minimum resolution product criteria. The minimum resolution product criterion proved to be most successful. An advantage of the described system is the improvement in peak shapes obtained after addition of hexanesulfonate to the electrolyte, resulting in increased plate numbers and better resolution. The system was very robust with mobilities varying by less than 2% over a period of days and on using different capillaries.
描述了使用电动色谱法，以可溶性阳离子聚合物聚二烯丙基二甲基氯化铵（PDDAC）和两亲性阴离子己烷磺酸盐的混合物作为假固定相，对一系列芳香族羧酸、磺酸盐和阿片类药物进行分离。在该系统中，PDDAC假固定相与阴离子分析物相互作用，而己烷磺酸盐假固定相与阳离子分析物相互作用。推导了一个迁移模型，该模型考虑了阴离子与阳离子PDDAC之间的离子交换（IE）相互作用以及阿片类药物与己烷磺酸盐之间的离子对（IP）相互作用。PDDAC - 己烷磺酸盐复合体系与疏水性更强的分析物之间的进一步相互作用也很明显，并在模型中予以考虑。应用该模型获得的常数与阴离子对PDDAC的IE亲和力的预期趋势吻合良好，并且也与分析物的疏水性质相符。使用归一化分离度乘积和最小分离度乘积标准对PDDAC和己烷磺酸盐的浓度进行了优化。结果证明最小分离度乘积标准最为成功。所描述系统的一个优点是在电解质中添加己烷磺酸盐后峰形得到改善，从而使塔板数增加且分离度更好。该系统非常稳定，在数天时间内以及使用不同毛细管时迁移率变化小于2%。
