Determining the 59 Chemical Drugs Illegally Added in Herbal Tea by a Micro-QuEChERS-Based UPLC-MS/MS

Objective: An analysis method for simultaneous determination of 59 kinds of chemical drugs illegally added in herbal tea by micro-QuEChERS method combined with ultra performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) was established. Method: The samples were extracted by ultrasonic extraction from acetonitrile solution for 5 min and salted out with sodium chloride (NaCl) and anhydrous sodium sulfate (Na₂SO₄). Supernatant was purified with C₁₈ sorbent and separated on a ACQUITY HSS T3 column (100 mm×2.1mm, 1.8 μm) by gradient elution using a mixture of 0.01% formic acid and acetonitrile:methanol (8:2) as the mobile phase. Then the analytes were quantified by UHPLC-MS/MS in multiple reaction monitoring mode (MRM) via positive and negative electrospray ionization quantified by external standard method. Result: The coefficient of determination of the standard calibration curves for the 59 analytes were all above 0.9990. The limit of detection (LOD, S/N≥3) and the limit of quantitation (LOQ, S/N≥10) were 5.0~10.0 and 10.0~25 μg/L. At three spiked of 25.0, 50.0 and 100.0 μg/L, the average recoveries of 59 analytes were 60.3%~128.8% (n=6) with the relative standard deviations in the range of 1.0%～13.7%. Conclusion: The method developed was simple, sensitive, and had good purification effect. It could be applied for the rapid determination of 59 chemical drugs illegally added in herbal tea.