QuEChERS-超高效液相色谱-串联质谱法测定叶类蔬菜中5种植物生长调节剂的残留

建立了QuEChERS-超高效液相色谱-串联质谱(QuEChERS-UPLC-MS/MS)对叶类蔬菜中极性较弱的氯吡脲、多效唑、烯效唑和丙环唑以及强极性的矮壮素共5种植物生长调节剂多残留的检测方法。样品经QuEChERS法预处理，用含体积分数为1%乙酸的乙腈溶液提取，石墨化碳黑(GCB)和N-丙基乙二胺(PSA)净化，C18色谱柱分离，采用电喷雾离子化正离子扫描和多反应监测模式(MRM)检测，基质匹配标准溶液外标法定量。结果表明:在1~1 000 μg/L范围内，氯吡脲、多效唑、烯效唑、丙环唑和矮壮素5种植物生长调节剂的质量浓度与对应的峰面积间呈良好的线性关系，相关系数均大于0.999 3，检出限(LOD)为0.002~0.04 μg/kg，定量限(LOQ)为0.01 mg/kg。在0.01、0.1和0.5 mg/kg添加水平下，5种植物生长调剂在菜心、芥蓝和普通白菜中的平均回收率为71%~93%，相对标准偏差(RSD)为0.2%~10%。该方法快捷、简便、定量准确，适用于叶类蔬菜中同时检测氯吡脲、多效唑、烯效唑、丙环唑和矮壮素等植物生长调节剂的残留。

Determination of Five plant growth regulator residues in leafy vegetables by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry

A method for the simultaneous determination of low-polarity pesticide, such as forchlorfenuron, paclobutrazol, uniconazole and propiconazole, and high polarity pesticide, such as chlormequat chloride in leafy vegetables was developed using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Vegetable samples were extracted by acetonitrile containing 1% (V%) acetic acid. Then they were cleaned up by GCB and PSA adsorbents before separated on a C18 column and detected under positive polarity multiple reactions monitoring (MRM) mode. The matrix-matched external standard calibration curves were used for quantitative analysis. The linearity of 5 plant growth regulators was in the range of 1-1 000 μg/L, with correlation coefficients higher than 0.999 3. The limits of detection (LOD) of the proposed method were 0.002 to 0.04 μg/kg. The limit of quantification (LOQ) was 0.01 mg/kg which was the lowest spiked concentration. Recoveries at three spiked levels of 0.01, 0.1 and 0.5 mg/kg ranged from 71% to 93% with relative standard deviations (RSDs) from 0.2% to 10% in flowering Chinese cabbage, Chinese kale and pak-choi. The presented method is fast, simple and accurate, which can meet the requirements for the determination of residues of forchlorfenuron, paclobutrazol, uniconazole, propiconazole and chlormequat chloride in leafy vegetables.