Determination of paclitaxel and other six taxoids in Taxus species by high-performance liquid chromatography–tandem mass spectrometry

A method of high-performance liquid chromatography–tandem mass spectrometry (LC–MS-MS) has been developed for the trace analysis of paclitaxel and other six taxoids in three Taxus species including Taxus cuspidata, Taxus media and Taxus chinensis var. mairiei. Seven taxoids were separated using a gradient mode on an Eclipse XDB-C18 column (4.6 × 150 mm; i.d., 5 μm) at 20 °C. The compound separations were detected by an API 3000 mass spectrometer equipped with a TurboIonSpray™ interface. The compounds were detected using electrospray ionization (ESI) in positive-ion mode and quantified by multiple-reaction monitoring (MRM) mode using the transition mass of m/z 567.4 → 445.4, 609.3 → 549.5, 944.9 → 286.4, 812.6 → 286.1, 832.8 → 264.1, 854.4 → 286.1, and 812.6 → 286.1 for 10-DAB III, baccatin III, 7-xyl-10-DAT, 10-DAT, cephalomannine, paclitaxel, and 7-epi-10-DAT, respectively. The ranges of limit of quantitation (LOQ) for taxoids were 32, 14, 26, 14, 20, 32, and 26 ng/mL for 10-DAB III, baccatin III, 7-xyl-10-DAT, 10-DAT, cephalomannine, paclitaxel, and 7-epi-10-DAT, respectively. Linearity was confirmed over the whole calibration range (0.07–45, 0.058–37.5, 0.058–37.5, 0.056–36.3, 0.053–33.8, 0.057–37.5, and 0.06–38.8 μg/mL for 10-DAB III, baccatin III, 7-xyl-10-DAT, 10-DAT, cephalomannine, paclitaxel, and 7-epi-10-DAT, respectively) with coefficients higher than 0.9903. The inter- and intra-day precision of taxoids ranged from 2.86% to 6.31% for retention time and ranged from 3.91% to 7.33% for peak area. The recovery rates of this method were higher than 94.32% for 10-DAB III, 94.68% for baccatin III, 93.65% for 7-xyl-10-DAT, 93.29% for 10-DAT, 92.91% for cephalomannine, 93.41% for paclitaxel, and 93.06% for 7-epi-10-DAT, respectively.