顶空固相微萃取结合气相色谱-三重四极杆质谱法快速测定茶叶中11种酰胺类除草剂残留

利用顶空固相微萃取(HS-SPME)与气相色谱-三重四极杆质谱(GC-MS/MS)联用,建立了快速测定茶叶中11种酰胺类除草剂残留的检测方法。以全发酵红茶为基质,对影响萃取性能的因素(如萃取涂层种类、无机盐种类、水用量、盐用量、萃取温度和萃取时间)进行了优化。在最优条件下,选取绿茶、乌龙茶、红茶和普洱茶4种茶叶基质对方法学进行考察。结果表明,11种酰胺类农药在1~1 000μg/kg含量范围内线性关系良好,相关系数(r2)为0.992 5~0.999 9,定量下限为1~10μg/kg。11种农药在红茶、绿茶、乌龙茶和黑茶基质中3个添加水平下的平均回收率分别为70.3%~119.1%、85.2%~118.7%和74.6%~113.3%,相对标准偏差(RSD)均不大于17.4%。该方法操作简单、快速、灵敏度高、重现性好,可满足不同种类茶叶基质中11种酰胺类除草剂农药残留的检测要求。

Rapid Determination of 11 Amide Herbicides in Tea by Headspace Solid-phase Microextraction Combined with Gas Chromatography-Triple Quadrupole Mass Spectrometry

Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-triple quadrupole mass spectrometry(GC-MS/MS) was used for the rapid determination of 11 amide herbicide residues in tea.Various factors affecting extraction performance such as the types of extraction coatings,the type of inorganic salt,water consumption,salt dosage,extraction temperature and extraction time in HS-SPME were optimized by using the all fermented black tea matrix.Under the optimized conditions,four kinds of teas,i.e.geen tea,oolong tea,black tea and puer tea were selected for methodology validation.The results showed that the calibration curves of 11 amide herbicides were linear in the range of 1 1 000 μg/kg,with correlation coefficents(r2) of 0.992 5-0.999 9,and the limits of quantitation ranged from 1 μg/kg to 10 μg/kg.The average recoveries of the 11 pesticides in black tea,green tea,oolong tea and dark tea at three spiked levels were in the ranges of 70.3％-119.1％,85.2％-118.7％ and 74.6％-113.3％,respectively.The relative standard deviations(RSDs) were all not more than 17.4％ (n =5).With the advantages of simplicity,rapidness,high sensitivity and good reproducibility,the method could meet the requirements of detection of 11 amide herbicide residues in tea.