Integrating UPLC‐QTOF‐MS/MS and UPLC‐DAD to evaluate the influence of sulfur‐fumigated Paeoniae Radix Alba on the overall quality of three Si‐Wu‐Tang formulations

S-PRA could differentially affect the transfer rate of paeoniflorin sulfite and other bioactive components during the preparation of three SWT formulations and subsequently the overall quality thereof.