超高效液相色谱-串联质谱法测定茶叶和土壤中丁醚脲及其代谢物的残留

Determination of Diafenthiuron and Its Metabolites in Tea and Soil by Ultra Performance Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

建立了超高效液相色谱-串联质谱同时快速测定茶叶和土壤中丁醚脲及其代谢物残留量的方法。样品采用乙腈提取,加入乙酸铵和NaCl进行液液分配,PSA结合GCB进行固相分散萃取除杂质,Waters Acquity UP-LC BEH C18柱(100 mm×2.1 mm×1.7μm)分离,超高效液相色谱-串联质谱法测定。在2.0～4000μg/L浓度范围内,不同基质中丁醚脲均有较好的线性关系(r>0.99),检出限为0.5μg/L;在2.0～2000μg/L浓度范围内,不同基质中丁醚脲-脲均有较好的线性关系(r>0.99),检出限为0.2μg/L。在0.02、0.20和4.00 mg/kg添加水平下,除绿茶中的低浓度水平丁醚脲回收率较低(56.3%,64.1%)外,其余均介于70.8%～110.5%之间,相对标准偏差介于0.8%～14.4%之间,方法定量限为丁醚脲0.005 mg/kg、丁醚脲-脲0.002 mg/kg。利用本方法对丁醚脲在茶园田间残留实验样品进行测定,获得了较好的效果,方法快速、简单,能够满足残留检测的需要。

A rapid and convenient UPLC-MS/MS method for analysis of diafenthiuron and its metabolites in tea and soil has been developed and validated.The sample was extracted with acetonitrile,added ammonium acetate and sodium chlorid,after centrifugation,the upper solvent was cleaned-up by N-propylethyl-diamine（PSA） and graphitizing of carbon black（GCB）,then determined by UPLC-MS/MS coupled with Waters Acquity UPLC BEH C18 column（100 mm×2.1 mm×1.7 μm）.Sample matrix-matched calibration was used to determine the residue contents by external standard.Over the concentration in the range of 2.0-4000 μg/L（2.0-2000 μg/L） for diafenthiuron（diafenthiuron-urea） in different matrix,the correlation coefficients（r） of the calibration curves were above 0.99,and the limits of detection（LODs） were 0.5 μg/L（0.2 μg/L） for each other.The recoveries of diafenthiuron and diafenthiuron-urea in fresh tea leaves,green tea,black tea and soil at three spiked concentration levels of 0.020,0.200 and 4.00 mg/kg ranged from 70.8% to 110.5% with relative standard deviations（RSDs） between 0.8% and 14.4%（n=5）,except for the recoveries of diafenthiuron in green tea at the lower level（56.3%,64.1%）.The limits of quantitation（LOQs） of diafenthiuron and diafenthiuron-urea were 0.005 mg/kg and 0.002 mg/kg,respectively.For validated,this method has been applied to the determination of diafenthiuron and its metabolites in field treatment experimental samples with a good result.