Quantitative analysis of different batches of raw, wine-processed, and vinegar-processed Paeoniae Alba Radix using ultra-performance convergence chromatography coupled with photo diode array detection (UPC 2 -PDA).

Supercritical fluid chromatography (SFC) is a safe and ecofriendly analytical technique that has not been fully applied to the analysis of traditional Chinese medicine (TCM). This is the first study on the separation of six quality markers (Q-markers) including paeoniflorin, albiflorin, benzoyl paeoniflorin, oxypaeoniflorin, gallic acid, and benzoic acid from raw, wine-baked, and vinegar-baked Paeoniae Alba Radix (PAR) by SFC. Optimum separation was achieved on an HSS C18 SB column (100×3.0 mm, 1.8 μm particles) with a gradient elution of high-purity carbon dioxide as mobile phase A and methanol/acetonitrile (70:30, v/v) with 0.10% phosphoric acid as mobile phase B. The flow rate was set at 0.7 mL/min for 15.0 min. The method was validated in terms of the overall intraday and interday precision, with relative standard deviation (RSDs) of 0.87-2.87% and 1.47-3.63%, respectively. The recoveries were 98.10-103.60% with an RSD of 1.00-3.40%. The stability of the RSD values was in the range of 1.10-3.78%. The developed approach was successfully applied and provides a valuable reference for the quality assessment of PAR and processed PAR. The results also revealed that the standardization of processing technology is of great significance to the fluctuations in quality before and after the processing of TCM.