Super critical method transfer: Inter-manufacturer qualification and comparison of three SFC instruments

In contrast to liquid chromatography (LC), in supercritical fluid chromatography (SFC) small changes in instrument setup and configuration can affect solvent density, which causes selectivity changes. Therefore, method transfer is less trivial than in LC. Moreover, depending on the manufacturer, different modes of operation will affect the results. For this research, methods were developed on a Waters UPC² instrument and replicated on an SFC system of Shimadzu, namely Nexera UC, and Agilent's 1260 Infinity II SFC, respectively. The comparison of the three instruments based on a systematic qualification was the basis for subsequent method transfer. Gradient tests to characterise gradient accuracy and precision, as well as to determine the dwell volume and pump performance of each system, were carried out. Further, the injection reproducibility was evaluated, which lead to insights into injection modes of each system and the effect of different manufacturers. As the Agilent system employs feed injection of samples, and the Shimadzu instrument is capable of co-injection approaches, investigations into minimising solvent strength effects were of particular interest. Following these experiments, a method for the separation of configurational isomers of vitamin A acetate was transferred and evaluated on all three instruments. Despite the inherently lower robustness of SFC compared to LC, the results presented here demonstrate the feasibility of method transfer while also showcasing characteristics of the SFC technique. Moreover, this research shall give an overview of the instrument options and how the differences in setup affect the separation.