Simultaneous determination of five anthraquinones in medicinal plants and pharmaceutical preparations by HPLC with fluorescence detection

A reversed-phase high-performance liquid chromatography (RP-HPLC) method with fluorescence detection for simultaneous determination of five anthraquinones in Rhubarb collected from nine different locations in China, Polygonum cuspidatum, Polygoni multiflori and three pharmaceutical preparations is proposed and validated. Chromatography was carried out at 25 °C on a Hypersil C18 column with the isocratic mobile phase of methanol–0.1% aqueous formic acid (85:15, v/v) at a flow rate of 1.0 ml/min. The excitation and emission wavelengths were set at 440 and 540 nm, respectively. A comprehensive validation of the method included tests of sensitivity, linearity, precision and accuracy. The linear regressions were acquired with r > 0.999. Satisfactory intra- and inter-day precisions were achieved with R.S.D.s less than 3.95% and the average recovery factors obtained were in the range of 93.2–103.8%.