晒青毛茶中37种除草剂农药残留气相色谱-串联质谱测定

目的采用气相色谱-串联质谱建立晒青毛茶中37种除草剂残留量的检测方法。方法茶叶样品经乙腈过夜浸泡、常温常压振摇提取后,采用商品化固相萃取柱(solid phase extraction column, SPE)小柱净化、浓缩,以环氧七氯为内标、正己烷定容,气相色谱-串联质谱(gas chromatography-tandem mass spectrometry,GC-MS/MS)在多反应监测(multiple reaction monitoring, MRM)模式下对37种除草剂进行定性、定量分析。通过检出限、定量限、加标回收率、线性范围验证方法的可行性。结果 37种农药在0.025～0.8 mg/L范围内均呈现良好的线性关系,相关系数r~2均大于0.995;方法的检出限和定量限范围分别为0.0007～0.05mg/kg和0.002～0.09 mg/kg;在0.025、0.05、0.1 mg/kg 3个加标水平下,其加标回收率为72.4%～109.8%,相对标准偏差均小于8%。结论该方法检出限、定量性、精密度、准确性和回收率均满足茶叶中除草剂农药残留测定的要求。

Determination of 37 herbicide residues in sun dried green tea using gas chromatography-tandem mass

Objective A gas chromatography-tandem mass spectrometric (GC-MS/MS) method has been developed for simultaneous determination of 37 herbicide residues in sun dried green tea. Methods The target analyses were extracted with acetonitrile by shaking under room pressure and temperature, purified by commercialized SPE pillar followed concentration, dissolved by epoxy heptachlor as internal standard and determined using n-hexane. The qualitative and quantitative analysis of the 37 herbicide residues were detected by GC-MS/MS with multi-reaction-monitor (MRM) mode. The method was validated according to the limit of detention, limit of quantitative, the percentage of recovery and linearity range. Results All the 37 pesticides showed good linear relationship in the range of 0.025~0.8 mg/L, and the correlation coefficient r2 was greater than 0.995. The detection limit and quantitative limit were 0.0007?0.05 mg/kg and 0.002?0.09 mg/kg, respectively. At the standard addition levels of 0.025, 0.05 and 0.1 mg/kg, the standard addition recovery was 72.4%?109.8%, and the relative standard deviation was less than 8%. Conclusion The detection limit, quantification, precision, accuracy and recovery all meet the requirements of determination of herbicide pesticide residues in tea.