Identification and Quantification of Four Anthraquinones in Rhubarb and its Preparations by Gas Chromatography-Mass Spectrometry.

A gas chromatographic-mass spectrometric (GC-MS) method was developed for the determination of four anthraquinones found in rhubarb. Chrysophanol, physcion, aloe-emodin and emodin were confirmed by GC-MS and the possible main cleavage pathways of fragment ions are discussed in this study. Rhubarb is a traditional Chinese medicinal herb which required an effective evaluation method to quantitate the four major active anthraquinone compounds described. The determinations of analytes were accomplished by GC-MS using osthole as an internal standard. MS detection was performed in selected ion monitoring mode to increase the sensitivity. The method was evaluated by a number of validation characteristics (precision, limit of detection, calibration range and recovery). The calibration ranges were all 3.2-30.0 μg/mL. This method was fully validated and showed good performances in terms of recovery (96.9-102.9%) and precision (1.4-2.9%). Finally, the method was applied to the analysis of four anthraquinones in rhubarb and its preparations in the first time.