[Determination of twelve chemical drugs illegally added in herbal tea by ultra high performance liquid chromatography-tandem mass spectrometry coupled with modified QuEChERS].

An ultra high performance liquid chromatography-tandem mass spectrometry method with modified QuEChERS procedure for sample preparation was developed for the simultaneous determination of 12 chemical drugs (chlorpheniramine, piroxicam, α-asarone etc) illegally added in herbal tea. The samples were extracted with acetonitrile, purified with QuEChERS procedure and filtrated by 0.22 μm microporous filters. The separation was carried on an XBridge BEH C18 column (100 mm x 2.1 mm, 3.5 μm) by a gradient elution using acetonitrile/0.1% (v/v) formic acid aqueous solution as mobile phases. The analytes were detected by tandem mass spectrometry with positive electrospray ionization (ESI+) in multiple reaction monitoring (MRM) mode, and quantified by external standard calibration method. The correlation coefficients of the standard calibration curves for the 12 analytes were all above 0.997. The limits of detection ranged from 0.1 μg/L to 2.1 μg/L, and the limits of quantification ranged from 0.4 g/L to 8.0 μg/L. The average recoveries of the 12 analytes spiked at three levels in blank samples ranged from 62.7% to 95.2% with the RSDs from 1.3% to 10.8%. The samples bought from markets were screened, and some of the samples showed positive for these analytes. The method developed is easy to operate, sensitive, and with good purification effect. It can be applied to the rapid determination of the 12 chemical drugs illegally added in herbal tea.