QuEChERS结合LC-MS/MS同时测定虾肉中72种兽药残留

建立了虾肉中72种兽药残留的QuEChERS结合液相色谱串联质谱测定的分析方法。样品经5%醋酸乙腈均质提取离心后，上清液依次用C18净化、乙腈沉淀蛋白、氮吹浓缩，0.1%甲酸-乙腈（4∶1,体积比）定容，0.22 μm滤膜过滤，LC-MS/MS测定，外标法定量。流动相为0.1%甲酸和乙腈，色谱柱为ZORBAX SB-C18，采用梯度洗脱模式进行色谱分离；离子源为电喷雾离子源（ESI），多重反应监测模式（MRM）。在0.1~1 840 μg/kg范围内，97.2%的目标兽药的线性相关系数大于0.95，定量下限范围为0.02~33.58 μg/kg。除熊脱氧胆酸、头孢吡啉、头孢喹咪、头孢噻呋、林可霉素、二嗪哝的回收率为38%~58%外，其它目标化合物的回收率为61%~119%，相对标准偏差为1.6%~20%，满足各国的限量法规要求。对市售的海虾、凤尾虾仁、青虾仁样品进行72种兽药残留筛查测定，海虾和凤尾虾仁中无检出；青虾仁样品中检出磺胺嘧啶和磺胺甲唑，检出量分别为4.0 μg/kg和2.2 μg/kg，均低于各国规定的限量要求。

Simultaneous Determination of 72 Veterinary Drugs in Shrimp by Modified QuEChERS and High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method was developed for the simultaneous determination of 72 veterinary residues in shrimps by QuEChERS and high performance liquid chromatography-tandem mass spectrometry.The sample was extracted with 5%acetic acid-acetonitrile,and the supernatant liquid was directly purified with C18,meanwhile,acetonitrile was used for the precipitation of protein.The extract was evaporated under nitrogen stream,and redissolved with 1 mL 0.1%formic acid-acetonitrile(4 ∶ 1).Prior to the injection into LC-MS/MS,the sample was filtered through a 0.22 μm filter membrane.The HPLC separation was performed on ZORBAX SB-C18 column by gradient elution with acetonitrile and 0.1%formic acid as mobile phase.The analysis of target compounds was carried out with electrospray ionization(ESI) under multi-reaction monitoring(MRM) mode.The external standard method was used for quantification.Under the optimal conditions,the correlation coefficients for 97.2%of the veterinaries were larger than 0.95 in the linear range of 0.1-1 840 μg/kg,the limits of quantitation ranged from 0.02 μg/kg to 33.58 μg/kg.The recoveries of 72 veterinary at three spiked levels were between 61%and 119%,except that for dibutylsuccinate,cefapirin,cefquinome,ceftiofur,lincomycin ane diazinon were between 38%and 58%,and their relative standard deviations were in the range of 1.6%-20%.The established method was used for the screening and determination of real samples(pteris shrimp,freshwater shrimp and sea shrimp) bought from supermarket.It was shown that no residue was detected in the sea shrimp and pteris shrimp samples,and 4.0 μg/kg of sulfadiazine as well as 2.2 μg/kg of sulfamethoxazole were found in freshwater shrimp sample,but the concentrations were all lower than the MRLs.