液相色谱-串联质谱法测定蔬菜和水果中6种新型酰胺类杀菌剂的残留量

Determination of six novel amide fungicides in vegetables and fruits by liquid chromatography-tandem mass spectrometry

建立了蔬菜、水果中啶酰菌胺、氟啶酰菌胺、环氟菌胺、嘧菌胺、双炔酰菌胺和硅噻菌胺6种新型酰胺类杀菌剂残留量的液相色谱-串联质谱（liquid chromatography-tandem mass spectrometry，LC-MS／MS）检测方法。试样经乙腈提取、Florisil固相萃取柱净化、以乙腈和水为流动相梯度洗脱、结合新型核壳型填料色谱柱（Poroshell 120 EC-C18）分离，采用电喷雾正离子扫描、多反应监测模式质谱检测，外标法定量。结果表明：固相萃取结合新型色谱柱分离解决了酰胺类农药分析中基质效应强的难点问题．6种杀菌剂在05～100μg／L范围内线性关系良好，相关系数（r）≥0．9990；对7种蔬菜及3种水果进行0.5、5和50μg／kg3个加标水平的回收试验，回收率为65％～124％，相对标准偏差（RSD，n=5）为1％～18％；6种杀菌剂的方法检出限（S／N≥3）为0．10～0．17μg／kg。该净化、分离模式显著降低了蔬菜、水果中6种新型酰胺类农药的基质效应，方法简单准确，可满足蔬菜和水果中啶酰菌胺等6种新型酰胺类杀菌剂残留检测的要求。

A method was developed for the simultaneous determination of mepanipyrim, silthiofam, boscalid, fluopicolide, mandipropamid, cyflufenamid in vegetables and fruits by liquid chromatography-tandem mass spectrometry （LC-MS/MS）. The analytes were extracted from the samples by acetonitrile and purified by Florisil SPE. The six novel amide fungicides were separated on a Poroshell 120 EC-C18 column with the mobile phases of water and acetonitrile, and finally detected by MS/MS with positive electrospray ionization （ ESI ＋ ） in multiple reaction monitoring （MRM） mode, quantified by external standard method. Under the optimal analytical conditions, the correlation coefficients （r） of the six novel amide fungicides were not lower than 0. 999 0 in the concentration range from 0.5 to 100 μg/L. The limits of detection （S/N≥3） of the method were 0. 15 μg/kg for boscalid, silthiofam, mandipropamid, cyflufenamid, 0. 10 μg/kg for mepanipyrim and 0. 17 μg/kg for fluopicolide. The recovery tests were performed for the 7 types of vegetables and the 3 types of fruits at the spiked levels of 0.5, 5 and 50 μg/kg, and the recoveries of the six analytes ranged from 65% to 124% with the relative standard deviations （ RSDs, n = 5 ） of 1% - 18%. The matrix effects in vegetables and fruits of the six amide fungicides were significantly reduced by the purification of Florisil SPE compared with the modified QuEChERS. The method is easy, fast, sensitive and accurate, and can meet the requirements of the determination of the six amide fungicide residues in vegetables and fruits.