超高效液相色谱-串联质谱法快速检测番茄酱中吡虫啉等6种农药残留

建立了番茄酱中吡虫啉、多菌灵、甲基硫菌灵、霜霉威、灭多威和烯酰吗啉等农药残留的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。样品用含0.1%(体积分数)乙酸的甲醇-水(1:1, v/v)混合溶液提取,采用Waters Acquity UPLC BEH C18色谱柱,以甲醇和10 mmol/L乙酸铵溶液为流动相进行梯度洗脱分离,经电喷雾正离子(ESI+)电离及多反应监测(MRM)模式来测定目标化合物,采用基质标准溶液曲线法进行定量。结果表明: 6种农药在0.005～0.2 mg/L的范围内线性关系良好(r＞0.995);当标准添加水平为0.02、0.05和0.2 mg/kg时,回收率为66.8%～102.9%;相对标准偏差均小于15%; 6种农药的定量限（以信噪比（S/N）＞10计）均为0.02 mg/kg。该方法简便、快速、灵敏和准确,非常适合番茄酱中这6种农药残留的快速检测及定量分析。

Rapid determination of 6 pesticide residues in tomato paste by ultra performance liquid chromatography-tandem mass spectrometry

An ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was established for the simultaneous determination of imidacloprid, carbendazim, thiophanate-methyl, propamocarb, methomyl and dimethomorph residues in tomato paste. The samples were extracted by methanol-water (1: 1, v/v) containing 0.1% (v/v) acetic acid. The separation was performed on a Waters Acquity UPLC system with a BEH C18 column with the gradient elution of methanol and water (containing 10 mmol/L ammonium acetate). The six pesticides were determined in the modes of electrospray positive ionization (ESI+) and multiple reaction monitoring (MRM). The analytes were quantified by matrix-matched standard solution, and the calibration curves showed good linearity within the concentrations of 0.005 to 0.2 mg/L and the correlation coefficients (r) were more than 0.995. The average recoveries of the six pesticides ranged from 66.8% to 102.9% in the three spiked levels of 0.02, 0.05 and 0.2 mg/kg. The relative standard deviations (RSDs) were all less than 15%. The limits of quantification (LOQ, S/N > 10) were 0.02 mg/kg for the all analytes. The results indicate that the method is easier, faster, more sensitive, and suitable for the qualitative and quantitative confirmation of the six pesticide residues from tomato paste.