The use of stationary-phase optimized selectivity in liquid chromatography (SOS-LC) was shown to be successful for HPLC to analyze complex mixtures using a Phase OPtimized Liquid Chromatography (POPLC) kit. This commercial kit contains five stationary-phase types of varying lengths, which can be coupled to offer an improved separation of compounds. Recently, stationary-phase optimized selectivity supercritical fluid chromatography (SOS-SFC) has been introduced, transferring the methodology to SFC. In this study, the applicability of a customized POPLC expert kit for isocratic SFC runs was explored. Five stationary-phase chemistries were selected as potentially most suitable for achiral separations of polar compounds: aminopropyl (amino), cyanopropyl (CN), diol, ethylpyridine (EP), and silica. The retention factors (k) on the individual stationary phases were used for the prediction of the best stationary-phase combination, based on the POPLC algorithm (via the included software). As an alternative, the best column combination was predicted using multiple linear regression (MLR) models on the results obtained from a simplex centroid mixture design with only three stationary-phase types (amino, silica, and EP). A third approach applied the isocratic POPLC algorithm on the same three stationary-phase data. The proposed combinations were assembled and tested. The predicted and experimental retention factors were compared. The predictions based on the POPLC algorithm provided a stationary phase showing a complete separation of the mixture. The stationary phase suggested by the MLR models, on the other hand, showed co-elution of two compounds, due to an unexpected experimental retention shift. Overall, the customized POPLC kit showed good potential to be applied in SFC.

Graphical abstract

经证明，在液相色谱 (SOS-LC) 中使用固定相优化的选择性可成功用于 HPLC 使用相优化液相色谱 (POPLC) 试剂盒分析复杂混合物。该商业套件包含五种不同长度的固定相类型，可以将它们耦合以提供更好的化合物分离。最近，已引入固定相优化选择性超临界流体色谱 (SOS-SFC)，将方法转移到 SFC。在本研究中，探讨了定制 POPLC 专家套件对等度 SFC 运行的适用性。选择了五种可能最适合极性化合物非手性分离的固定相化学品：氨基丙基（氨基）、氰丙基 (CN)、二醇、乙基吡啶 (EP) 和硅胶。保留因子 ( k) 用于基于 POPLC 算法（通过附带的软件）预测最佳固定相组合。作为替代方案，使用多元线性回归 (MLR) 模型对从仅具有三种固定相类型（氨基、硅胶和 EP）的单纯形心混合物设计获得的结果进行预测，从而预测最佳色谱柱组合。第三种方法对相同的三个固定相数据应用等度 POPLC 算法。组装并测试了建议的组合。比较了预测的和实验的保留因子。基于 POPLC 算法的预测提供了显示混合物完全分离的固定相。另一方面，MLR 模型建议的固定相显示两种化合物的共洗脱，由于意外的实验保留变化。总体而言，定制的 POPLC 套件在 SFC 中显示出良好的应用潜力。

图形概要