UHPLC–MS/MS method for the simultaneous quantitation of five anthraquinones and gallic acid in rat plasma after oral administration of prepared rhubarb decoction and its application to a pharmacokinetic study in normal and acute blood stasis rats

Prepared rhubarb, as one of the main processed products of rhubarb, has a good effect on promoting blood circulation. In this paper we describe a rapid, sensitive, and selective ultra‐fast liquid chromatography with tandem mass spectrometry method for simultaneous quantification of five anthraquinones (rhein, aloe‐emodin, chrysophanol, emodin, and physcion) and gallic acid in plasma. Chromatographic separation was performed on an Extend C₁₈ column at the temperature of 30°C using a mobile phase that consisted of 0.1% aqueous formic acid and acetonitrile. Satisfactory linearity, precision, accuracy, extraction recovery, and matrix effect have been achieved. Then, the validated method was successfully applied to a comparative pharmacokinetic study. The results might be helpful for guiding clinical application of prepared rhubarb in the future.