Stationary-phase optimized selectivity in supercritical fluid chromatography using a customized Phase OPtimized Liquid Chromatography kit: comparison of different prediction approaches

Abstract

The use of Stationary-phase Optimized Selectivity in Liquid Chromatography (SOS-LC) was shown 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.

Achiral SFC separations: Gold standard for the next generation of nontarget screening

“…The selectivity of the combined stationary phases will not be a combination, but a sequential add‐up. In SFC, the ‘additive’ effect is possible using the POPLC style with isocratic mobile phases like in classical LC, 9 as well as with mobile phase gradients. 8…”

Leveraging the power of supercritical fluid chromatography for eco-conscious solutions in pharmaceutical analysis

“…In addition to the well-known QSRR-LSER approaches, Grooten et al (71) recently proposed the tailored Phase Optimized Liquid Chromatography (POPLC) algorithm and a commercial kit for SFC method development. This approach aids in selecting the optimal combination of achiral columns, involving the coupling of five stationary phases with different chemistries (aminopropyl, cyanopropyl, diol, EP and bare silica gel) and varying lengths.…”

Coupling of chiral and achiral stationary phases in supercritical fluid chromatography: Evaluating and improving retention prediction

“…Correspondence between calculated (kcal) and experimentally obtained retention factors (kexp) values was assessed by the relative deviation (RD) [32]:…”