Abstract: A rapid, specific and sensitive ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of four trace alkaloids, including aconitine (AC), hypaconitine (HA), mesaconitine (MA) and yunaconitine (YA) in human urine samples. UPLC-MS-MS system coupled with an electrospray ionization (ESI) source was performed in multiple reaction monitoring (MRM) mode. The sample preparation was performed with hollow fiber microextraction (HF-LPME) prior to the analysis. The enrichment factors of the four alkaloids were 102-301. The separation was applied on a Waters ACQUITY UPLC BEH C18 column (50 mm×2.1 mm, 1.7 μm) with a gradient elution of acetonitrile and 10 mmol/L NH4HCO3 as mobile phase. The retention times were less than 3 min. This method significantly improved the detection sensitivity, and the limits of quantitation were from 0.01 to 0.1 ng/L. The calibration curves were linear over the ranges of 0.01-10 ng/L for AC, MA and YA, 0.1-100 ng/L for HA in human urine samples, and the correlation coefficients were 0.9981, 0.9984, 0.9995 and 0.9986, respectively. The method was proved to be rapid and sensitive for aconitum alkaloid analysis in urine samples.

Key words: aconitine, hypaconitine, mesaconitine, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), urine samples, yunaconitine, hollow fiber liquid-phase microextraction (HF-LPME)