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建立了QuEChERS前处理-液相色谱-串联质谱仪(HPLC-MS/MS)测定植物源食品中氟噻草胺和乙酰甲草胺残留量的分析方法。样品经酸化乙腈(含0.1%甲酸的乙腈)提取,采用石墨化碳黑(GCB)净化,提取液经离心、过膜后直接上机检测。该方法采用C18色谱柱进行色谱分离,以0.1%甲酸水(含5mmol/mL乙酸铵)-甲醇为流动相,在0.25mL/min流速下梯度洗脱,电喷雾正离子电离(ESI+),多重反应监测模式(MRM)检测,以保留时间和特征离子对(母离子和两个碎片离子)信息比较进行定性,基质匹配曲线定量。在9种基质(葡萄、葡萄干、黄瓜、小麦粉、苹果、白菜、枸杞、西红柿和大米)中,氟噻草胺和乙酰甲草胺在0.25~25.0μg/L范围内线性关系良好,相关系数均大于0.997,两种化合物的方法定量限为0.5μg/kg;在0.5,1.0,5.0μg/kg3个添加水平下,氟噻草胺的平均回收率在82.5%~103.9%,相对标准偏差为2.9%~15%;乙酰甲草胺的回收率在81.7%~108.1%,相对标准偏差在3.1%~14%。方法灵敏度、准确度和精密度均符合农药残留检测要求。
A method for the determination of flufenacet and carboxamide residues in plant-derived foods by QuEChERS pretreatment-liquid chromatography-tandem mass spectrometry (HPLC-MS / MS) was established. The sample was extracted with acidified acetonitrile (0.1% formic acid in acetonitrile) and purified with Graphitized Carbon Black (GCB). The extract was centrifuged and tested directly on the membrane. The method was performed on a C18 column with a mobile phase consisting of 0.1% formic acid in water (containing 5 mmol / mL ammonium acetate) -methanol, gradient elution at 0.25 mL / min, electrospray positive ionization (ESI +), Response monitoring mode (MRM) assay was used to characterize the retention time and information of characteristic ion pair (precursor and two fragment ions), and the matrix matching curve was quantified. There was a good linear relationship between flufenacet and acetyllachlor in the range of 0.25 ~ 25.0 μg / L in nine kinds of substrates (grape, raisin, cucumber, wheat flour, apple, cabbage, Chinese wolfberry, tomato and rice) > 0.997, and the limit of quantification of the two compounds was 0.5μg / kg. The mean recoveries of flufenacet ranged from 82.5% to 103.9% at the three spiked levels of 0.5, 1.0 and 5.0μg / kg with the relative standard deviation of 2.9 % ~ 15%; the recovery rate of acetylcholine 81.7% ~ 108.1%, the relative standard deviation of 3.1% to 14%. The method sensitivity, accuracy and precision are in line with pesticide residue testing requirements.