高效液相色谱-串联质谱法同时检测牛乳中11种农药残留量

采用高效液相色谱-串联质谱仪，建立一种可以同时检测牛乳中多种农药残留的分析方法。样品经乙腈提取，氯化钠、硫酸镁分层，经过2 次提取后，用C18固相萃取柱净化，流出液旋转蒸发至干后用乙腈复溶后上机测定。采用C18色谱柱进行分离，以5 mmol/L乙酸铵（含0.1%甲酸）-甲醇为流动相进行梯度洗脱，电喷雾离子化模式在多反应监测模式下测定。结果表明：啶虫脒、涕灭威、噻虫胺、甲胺磷、氟酰脲、苯丁锡、螺螨酯、苯醚甲环唑、噻草酮、氰氟虫腙及二甲四氯11 种农药在质量浓度0～100 ng/mL范围内线性良好，相关系数（R2）均大于0.995 0；对不含农药残留的牛乳样品进行3 个添加水平（1、2、4 μg/L）的测定，11 种农药的平均加标回收率为40.2%～99.2%，相对标准偏差均小于18.9%，方法检出限为1.00 μg/L；该方法可以快速、灵敏测定牛乳中11 种农药残留量。

Simultaneous Detection of 11 Pesticide Residues in Milk by High Performance Liquid Chromatography-Tandem Mass Spectrometry

In this paper, a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) methodwas proposed to simultaneously detect multiple pesticide residues in milk. The sample was extracted with acetonitrile, andpartitioned by adding sodium chloride and magnesium sulfate. The extraction was carried out twice, and then the extractwas purified with a C18 solid phase extraction column. Finally, the eluate was collected and evaporated to dryness after rotaryevaporation, and the resulting residue was redissolved prior to instrumental analysis. The chromatographic separation wasperformed on a C18 column using gradient elution with a mobile phase consisting of 5 mmol/L ammonium acetate (containing0.1% formic acid) and methanol. The detection was conducted using an electrospray ionization source under the multireactionmonitoring (MRM) mode. The results showed that the calibration curves for acetamiprid, aldicarb, clothianidin,methamidophos, novaluron, fenbutatin-oxide, spirodiclofen, difenoconazole, cycloxydim, metaflumizone and 2-methyl-4-chloro-phenoxyacetic acid (MCPA) had a good linearity in the concentration range of 0–100 ng/mL with correlationcoefficients (R2) all greater than 0.995 0. The average recoveries for blank milk samples at three spiked concentration levels(1, 2 and 4 μg/L) were 40.2%–99.2%, with relative standard deviation (RSD) less than 18.9%, and the detection limit of themethod was 1.00 μg/L. This method could allow quick and sensitive analysis of the contents of 11 pesticide residues in milk.