色谱法研究杂多酸—— Ⅲ.键合相表面残留硅醇基对杂多酸保留行为的影响

The Influence of Residual Silanol Groups of the Stationary Phase Surface on the Retention Behavior of Heteropoly Acids

在反相体系中,研究了十八烷基键合相表面残留硅醇基对杂多酸阴离子保留行为的影响。研究表明,在流动相pH<4,缓冲液浓度<3mmol·L^(-1)条件下。残留硅醇基对杂多酸阴离子存在保留作用,该作用随pH值、缓冲液浓度的降低而增加。在上述条件,杂多酸阴离子容量因子倒数与缓冲液浓度的关系为:k′^(-1)=A(Z^-)_m+B。在较高缓冲液(或盐)浓度时,流动相中阴离子对硅醇基的屏蔽,减少了对杂多酸阴离子的影响,降低了残留硅醇基对杂多酸阴离子的保留。

In the reversed-phase system, the influence of residual silanol groups of C18 bonded phase surface on the retention behaviors of heteropoly acid (HPA) anion is studied. It is shown that, when the pH value in the mobile phase is less than 4 and the concentration of buffer (as mobile phase) is less than 3 mmol · L-1, the residual silanol groups exert retention action on HPA anion. The less the pH value and the concentration of buffer, the stronger the retention action is. The relationship between the reciprocal of the capacity factor of HPA anion and the concentration of buffer can be described as kf-l= A (Z- ) m+B. At higher concentration of buffer the influence of residual silanol groups on HPA anion retention is decreased because of the present of the screen of anion in mobile phase, and the retention of HPA anion is also reduced.