Stationary-phase contribution of 1-propanol organic modifier to changes in sorption of 1-hexanol on an ODS-bonded phase
Stationary-phase contribution of 1-propanol organic modifier to changes in sorption of 1-hexanol on an ODS-bonded phase
复制标题
1-丙醇有机改性剂对 ODS 键合相上 1-己醇吸附变化的固定相贡献
DOI：
10.1021/ac990845x
复制
发表时间：
2000
影响因子：
7.4
通讯作者：
Cantwell
中科院分区：
文献类型：
--
作者：
Felitsyn;Cantwell
使用反相键合相HPLC填充Partisil-10 ODS-3，吸附等温线已被测量的醇1-丙醇（PrOH）和1-己醇（HexOH），以及，同时吸附曲线已被测量的两个醇从溶液中含有低浓度和恒定浓度的HexOH作为样品与浓度增加的PrOH作为有机改性剂。流动相的影响PrOH是定量的溶液相的活度系数从蒸汽/溶液平衡测量或从浊点测量。由于吸附醇位于ODS/溶液界面，固定相效应的PrOH建模在三个过程：（一）空间的竞争;（二）减少所需的空间每摩尔浓度的增加吸附的PrOH;和（iii）吸附的自由能的变化与浓度的增加吸附的PrOH。该模型产生很好的拟合等温线和同步吸附曲线。比较模型拟合参数的同时吸附曲线与那些为PrOH等温线证实，固定相效果的PrOH对HexOH是由于专门的过程i和ii。吸附的PrOH引起ODS相的C18链的重排。对于在移动的相中PrOH的体积百分比小于15%，PrOH对样品吸附的影响几乎完全在固定相中。在15%到30%之间，移动的和静止阶段的影响都很重要。
Using the reversed-phase bonded-phase HPLC packing Partisil-10 ODS-3, sorption isotherms have been measured for the alcohols 1-propanol (PrOH) and 1-hexanol (HexOH), and as well, a simultaneous sorption curve for the two alcohols has been measured from solutions containing a low and constant concentration of HexOH as sample with increasing concentrations of PrOH as organic modifier. The mobile-phase effect of PrOH is quantified by solution-phase activity coefficients obtained either from vapor/solution equilibrium measurements or from cloud point measurements. Since sorbed alcohols are located at the ODS/solution interface, the stationary-phase effect of PrOH is modeled in terms of three processes: (i) competition for space; (ii) decrease of space required per mole with increasing concentration of sorbed PrOH; and (iii) change of free energy of sorption with increasing concentration of sorbed PrOH. The model yields excellent fits to the isotherms and to the simultaneous sorption curve. Comparison of the model-fitting parameters for the simultaneous sorption curve with those for the PrOH isotherm confirms that the stationary-phase effect of PrOH on HexOH is due exclusively to processes i and ii. Sorbed PrOH causes rearrangement of the C18 chains of the ODS phase. For volume percent PrOH less than 15% in the mobile phase, the effect of PrOH on sample sorption is nearly exclusively in the stationary phase. Between 15 and 30%, both mobile- and stationary-phase effects are important.