Department of Analytical Chemistry, University of Pardubice, Pardubice, Czech Republic.
J Sep Sci. 2020 Jan;43(1):70-86. doi: 10.1002/jssc.201900920. Epub 2019 Nov 4.
Adopting a stationary phase convention circumvents problematic definition of the boundary between the stationary and the mobile phase in the liquid chromatography, resulting in thermodynamically consistent and reproducible chromatographic data. Three stationary phase definition conventions provide different retention data, but equal selectivity: (i) the complete solid phase moiety; (ii) the solid porous part carrying the active interaction centers; (iii) the volume of the inner column pores. The selective uptake of water from the bulk aqueous-organic mobile phase significantly affects the volume and the properties of polar stationary phases. Some polar stationary phases provide dual-mode retention mechanism in aqueous-organic mobile phases, reversed-phase in the water-rich range, and normal-phase at high concentrations of the organic solvent in water. The linear solvation energy relationship model characterizes the structural contributions of the non-selective and selective polar interactions both in the water-rich and organic solvent-rich mobile phases. The inner-pore convention provides a single hold-up volume value for the retention prediction on the dual-mode columns over the full mobile phase range. Using the dual-mode monolithic polymethacrylate zwitterionic micro-columns alternatively in each mode in the first dimension of two-dimensional liquid chromatography, in combination with a short reversed-phase column in the second dimension, provides enhanced sample information.
采用固定相定义惯例可以避免在液相色谱中固定相和流动相之间的边界的定义问题，从而得到热力学一致且可重现的色谱数据。三种固定相定义惯例提供不同的保留数据，但具有相同的选择性：(i) 完整的固相部分；(ii) 承载活性相互作用中心的固体多孔部分；(iii) 柱内孔的体积。从本体水相-有机流动相中选择性地吸收水会显著影响极性固定相的体积和性质。一些极性固定相在水相-有机流动相中提供双模式保留机制，在富含水的范围内为反相，在水相中有机溶剂浓度高时为正相。线性溶剂化能量关系模型表征了非选择性和选择性极性相互作用在富含水和有机溶剂的流动相中的结构贡献。内孔惯例为在双模式柱上在整个流动相范围内进行保留预测提供了单一的保留体积值。在二维液相色谱的第一维中，交替使用双模式的甲基丙烯酸酯两性离子整体微柱，在第二维中使用短的反相柱，可提供增强的样品信息。
