中文摘要：

建立了牛奶中8类禁用药物的液相色谱-串联质谱（LC-MS/MS）检测方法。分析物包括5种硝基咪唑、7种β-受体激动剂、9种雄性激素、7种糖皮质激素、3种雌性激素、2种镇静剂、1种氯霉素以及6种二羟基苯甲酸内酯共40种禁用药物。样品以β-葡萄糖苷醛酶/芳基硫酸酯酶在乙酸铵缓冲液中酶解,用氨化和酸化乙腈各提取一次。提取液经改良的分散固相萃取（QuEChERS）净化,浓缩后采用C18色谱柱分离（150mm×2.1mm i.d.,3.0μm）。以甲醇和水（含0.1%甲酸）、乙腈和水分别作为正、负电喷雾离子化模式的色谱分离流动相进行梯度洗脱,多反应监测模式进行定性和定量分析。7种药物以内标法定量;33种药物以基质标准曲线-外标法定量,氯霉素在0.02～0.4μg/kg;39种药物在0.20～10.0μg/kg范围内相关系数（r）均大于0.99;定量限（S/N=10）在0.07～0.93μg/kg之间。分别以各个药物0.5,1和2倍MRPL（Minimum required performance limits）浓度水平加标验证实验,回收率范围60.3%～119.3%范围;相对标准偏差小于18.9%。

英文摘要：

A method was developed for determination of 8 species of unauthorized drugs in bovine milk by liquid chromatography-tandem mass spectrometry（LC-MS/MS）.All target drugs covered 5 nitroimidazoles,7 β-agonists,9 androgens,7 glucocorticoids,3 estrogens,2 sedatives,1 chloramphenicol and 6 resorcylic acid lactones.After homogenization,the sample was mixed with β-glucuronidase/arylsulfatase for enzymatic reaction in ammonia acetate buffer and followed by extraction with basic and then acidic acetonitrile solutions.Cleanup of the extracts was processed by a modified dispersive solid phase extration（QuEChERS）.The analystes were then separated by a C18column（150 mm×2.1 mm i.d.,3.0μ） utilising gradient elution with methanol/water（containing 0.1% formic acid） and acetontrile/water,and finally detected by tandem mass spectrometry in positive/negative ESI mode.Identification and quantification were achieved by LC-MS/MS with multi-reaction monitoring.Isotope internal standards for 7 compounds and matrix-matched calibrations were respectively used to quantify the residue contents.Good linearity in response was obtained in the concentration range of 0.02-0.40 μg/kg for chloramphenicol and 0.20-10.0 μg/kg for the other 39 analytes,with correlation coefficients larger than 0.99.The limits of quantification（S/N=10） was around 0.07-0.93 μg/kg.Method validation was carried out at half minimum required performance limits（MRPL）,MRPL and double MRPL level of each substance,and the recoveries were in the range of 60.3%-119.3% with relative standard deviations（RSD） smaller than 18.9%.