色谱法研究杂多酸 II.杂多酸在反相高效液相色谱中的保留行为

Research on Heteropoly Anions with Chromatography Ⅱ. The Retention Behaviours of Heteropoly Anions in Reversed-Phase Liquid Chromatography

在十八烷基键合硅胶柱上,以甲醇-缓冲液作流动相,研究了杂多酸的容量因子随流动相离子强度、柱温、甲醇含量变化的规律,这些规律与我们导出的关系式相一致.对保留值作出贡献的有固定相排阻作用、分配作用以及居次要地位的杂多酸与固定相表面剩余硅醇基的相互作用.排阻作用与分配作用的相对重要性与流动相中甲醇含量有关.杂多酸可能形成了离子缔合物,其保留行为与一般的有机分子相似,但离子强度有影响.

The retention behaviour of heteropoly anions(HPAs)on an octadecyl-bonded silica column have been investigated.Mobile phases with or without the presence of ionpair reagent are used.In both cases,the HPAs are probably separated in the form of ion-associates.It is shown that the contributions to the retention of HPAs are from the steric permeation,the partition and less importantly,the interaction between HPAs and the residual silanol groups of the stationary phase.The most important factors that affects the retention values of HPAs are the charge numbers of the anions and the concentration of methanol in the mobile phase.In the system of methanol-buffer,the retention behavior of HPAs is similar to those of neutral organic molecules,but the ionic strength of mobile phase has some influences.When ion-pair reagents are used,the retention behavior deviates from that predicted from the dynamic ion exchange model.All the six HPAs investigated can be retained in the presence of ion-pair reagent under suitable conditions.