超高效液相色谱-串联质谱法检测盆栽辣椒中咯菌腈及精甲霜灵残留

Determination of fludioxonil and metalaxyl-M in potted peppers by ultra performance liquid chromatography-tandem mass spectrometry

目的建立一种同时检测盆栽辣椒中咯菌腈和精甲霜灵残留的超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS),明确灌根处理方式下2种化合物的降解动力学。方法样品经乙腈溶液提取,Qu ECh ERS方法净化,C18色谱柱分离,使用超高效液相色谱-串联质谱法进行测定。结果在0.0005~0.2 mg/L质量范围内,咯菌腈和精甲霜灵的质量浓度与峰面积线性关系良好(r2>0.99),定量限(limit of quantitation,LOQ)为0.0005 mg/kg;在添加水平为0.01、0.05和0.1 mg/kg时,咯菌腈和精甲霜灵在盆栽辣椒中的平均回收率为93.00%~111.60%,相对标准偏差(relative standard deviation,RSD)为0.28%~7.95%。咯菌腈和精甲霜灵在盆栽辣椒中的消解动态符合一级动力学模型,半衰期分别为5.4 d和8.7 d。按推荐剂量和1.5倍推荐剂量灌根施药后3~14 d,盆栽辣椒中咯菌腈的残留量小于0.0062 mg/kg;盆栽辣椒中精甲霜灵的残留量小于0.0790 mg/kg。结论该方法简单灵敏,定量准确,符合盆栽辣椒中咯菌腈和精甲霜灵残留测定的检测要求。

Objective To establish a method for simultaneous determination of fludioxonil and metalaxyl-M in potted pepper by ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）, and define the degradation kinetics of the 2 compounds under the irrigation method. Methods The target compounds were extracted with acetonitrile, purified by QuEChERS method, separated by C18 column, and determined by ultra performance liquid chromatography-tandem mass spectrometry. Results In the range of 0.0005-0.2mg/L, the mass concentration of fludioxonil and metalaxyl-M had a good linear relationship with the peak area （r^2〉0.99）, and the limits of quantitation （LOQ） were 0.0005 mg/kg. The average recoveries of fludioxonil and metalaxyl-M at 3 spiked levels （0.01, 0.05 and 0.1 mg/kg） ranged from 93.0% to 111.6%, with relative standard deviations （RSD） of 0.28% to 7.95%. The dissolution of fludioxonil and metalaxyl-M in potted pepper was in accordance with the first-order kinetic model, with half-life of 5.4 d and 8.7 d, respectively. The residues of fludioxonil and metalaxyl-M in potted peppers were lower 0.0062 mg/kg and 0.0790 mg/kg at the interval 3-14 d, respectively, after soil application at recommended dosage and 1.5-fold of recommended dosage. Conclusion This method is simple, sensitive, accurate, which can meet the requirements of the determination of the residue of rhizoma latticum and sericin in pot pepper.