液相色谱同位素稀释串联质谱法测定牛奶和奶粉中3种硝基咪唑类禁用兽药及其代谢物的残留量  

Determination of 3 kinds of banned nitroimidazole veterinary drug and their metabolites in milk and milk powder by liquid chromatography isotope dilution tandem mass spectrometry

作　　者：陈瑞春[1] 艾连峰[1] 郭春海[1] 王凤池[1] 

机构地区：[1]河北出入境检验检疫局,河北石家庄050051

出　　处：《中国食品卫生杂志》2011年第6期543-549,共7页Chinese Journal of Food Hygiene

摘　　要：目的建立了液相色谱同位素稀释串联质谱法同时测定牛奶和奶粉中3种硝基咪唑类禁用兽药(甲硝哒唑、二甲硝咪唑和罗硝哒唑)及其代谢物(羟基甲硝唑和1-甲基-2-羟甲基-5-硝基咪唑)残留量的方法。方法采用乙腈沉淀样品蛋白,乙酸乙酯提取目标物,强阳离子交换固相萃取柱净化提取液,液相色谱-串联质谱测定,同位素内标法定量。结果牛奶样品中5种分析物的检测限(LOQ)为0.5～1μg/kg,奶粉样品中5种分析物的LOQ为2.5～5μg/kg。5种分析物在0～50μg/L的浓度范围内呈良好线性,线性相关系数>0.995。方法在3个水平的添加回收率在88.3%～104.4%之间,相对标准偏差在3.67%～8.52%之间。结论方法采用同位素稀释法定量,回收率高、重现性好,适用于牛奶、奶粉等样品中硝基咪唑类药物残留的定量及确证检测。Objective A sensitive liquid chromatography-tandem mass spectrometry（LC-MS/MS） method was developed for the simultaneous determination of 3 kinds of banned nitroimidazole veterinary drug and their metabolites including metronidazole,ronidazole,dimetridazole,metronidazole-OH（the metabolite of metronidazole）,and 2-hydroxymethyl-1-methyl-5-nitroimidazole（the metabolite of ronidazole and dimetridazole） in milk and milk powder.Methods The protein in samples were precipitated with acetonitrile and the targets were extracted with ethyl acetate.Extracts were purified on a strong cation-exchange SPE column,and then LC-MS/MS analysis was performed on multiple reaction monitoring mode under positive ion electrospray ionization for each compound.Isotope dilution internal standard method was used for quantitation analysis.Results The limits of quantitation of 5 analytes are 0.5~1 μg/kg in milk and 2.5~5 μg/kg in milk powder.The linearity of standard curve at concentrations ranging from 0 to 50 μg/L is satisfactory with a correlation coefficient of 0.995.Average recoveries of the analytes fortified at three levels of standards were in the range from 88.3% to 104.4%.Conclusion The method was suitable for quantitative analysis and confirmation of nitroimidazole residues in milk samples.

关 键 词：液相色谱-串联质谱 同位素稀释 硝基咪唑类药物 代谢物 牛奶 奶粉 兽药残留 食品安全 

分 类 号：O657.63[理学—分析化学] O657.72[理学—化学]