建立了蔬菜水果中阿维菌素、伊维菌素、依普菌素、甲氨基阿维菌素苯甲酸盐B1a和甲氨基阿维菌素苯甲酸盐B1b的液相色谱-串联质谱(LC-MS/MS)检测方法.试样经乙腈提取,N-丙基乙二胺(PSA)和C18吸附剂分散固相萃取净化后,液相色谱-串联质谱分离测定.对流动相、梯度洗脱程序、去溶剂气体温度等进行了优化.结果表明:去溶剂气体温度为250℃时,5种阿维菌素均能形成稳定的[M+NH4]+准分子离子峰及相应的碎片离子,其线性范围均超过3个数量级,且相关系数大于0.999；对5种蔬菜和水果样品分别进行3个水平的加标回收实验(n=6),甲氨基阿维菌素苯甲酸盐B1a在0.2、20、200 μg/kg,其余分析物在2、20、200 μg/kg水平下,平均回收率为74％～110％,相对标准偏差(RSD)为0.4％ ～ 12.1％,5种阿维菌素的方法检出限分别为0.6、0.6、0.3、0.06、0.6μg/kg.该方法稳定、可靠,可满足蔬菜水果中阿维菌素类药物残留检测与确证的需要.%A liquid chromatography - tandem mass spectrometric method was developed for the simultaneous determination of 5 avermectin residues ( e. g. abamectin, ivermectine, eprinomectin, emamectin benzoate Bla and emamectin benzoate Blb) in fruits and vegetables. After extracted with acetonitrile, avermectin residues were cleaned up by PSA and C18 dispersive solid phase extraction. Influences of mobile phases, procedure of solvent gradient and temperature of the desolvation gas were investigated. Experimental results revealed that the most signal intense precursor ions( [ M + NH4 ] + ) were observed when desolvation gas temperature of 250 ℃ was used. The method was evaluated in terms of the limits of detection and quantitation. The linearity of the analytical response within the studied range of 3 orders of magnitude was excellent, with correlation coefficients higher than 0. 999. The mean recoveries of all analytes in 5 spiked fruits and vegetables matrix were in the range of 74% - 110% , with relative standard deviations of 0.4% -12.1%. The limits of detection for abamectin, ivermectine, eprinomectin, emamectin benzoate Bla and emamectin benzoate Bib were 0.6, 0.6, 0.3, 0.06, 0.6 μg/kg, respectively. The method was efficient, reliable and sensitive, and could meet the requirements for the determination of 5 avermectin residues in fruits and vegetables.
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