A One-Step Sample Pretreatment and Loading Method for Complex Sample Separation with Supercritical Fluid Chromatography

Solvent mismatches as well as impurity interference have become obstacles for supercritical fluid chromatog-raphy (SFC). In this study, a one-step sample pretreatment and loading method was developed for separation of Hedyotis diffusa (H. diffusa) with SFC. H. diffusa was firstly mixed with C18-bonded silica, and then subjected to a loading device, which was in line with a SFC column. Non-targeted components were firmly retained on C18-bonded silica in the condition of 100% CO2 at a flow rate of 15 mL/min for 10 min, while targeted fractions were eluted to the SFC column, where the targets were enriched and then separated. Thus, a one-step pre-treatment and direct loading of target components were achieved with the use of chromatographic material, which in turn solves the issue of solvent incompatible as well as co-existing impurities. Finally, a rapid and effective SFC separation of the targets in H. diffusa was achieved with sharp peaks.