高效液相色谱-串联质谱测定奶粉中3种苯并咪唑类药物残留

建立了高效液相色谱-串联质谱测定全脂和脱脂奶粉中奥芬达唑，阿苯达唑和芬苯达唑3种苯并咪唑类杀虫剂残留的方法。通过比较不同溶液的提取效率，最终选择含1%乙酸的甲醇作为提取溶液，正己烷和阳离子固相萃取两步净化，有效去除奶粉基质中的抑制干扰物。以乙腈和含0.5 mmol/L醋酸铵及0.1%甲酸的水溶液为流动相，C₁₈作为分析色谱柱，采用梯度洗脱方式进行液相色谱分离。脱脂奶粉和全脂奶粉3个添加水平的回收率范围为70.0%~85.8%，相对标准偏差均小于7.5%，在2～100 μg/L浓度范围内，线性相关系数大于0.997 3，方法检测限为10 μg/kg，能满足现有各国残留限量要求。

Determination of Three Benzimidazole Residues in Milk Powder Using HPLC-MS/MS

A method for simultaneous determination of oxfendazole,albendazole and fenbendazole residues in milk powder was developed by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).By comparison the extraction effect of different solutions,1% acetic acid-methanol was finally selected as the extracting solution.Two consecutive steps of N-hexane and cationic solid phase extraction were used to remove the interferences in milk powder.Gradient elution programme was performed on a C18 column using a mobile phase consisting of acetonitrile and 0.5 mmol/L ammonium acetate-0.1% formic acid solution.Recoveries of skim milk and whole milk powder are in the range of 70.0%—85.8%.The conrrelation coefficient is greater than 0.997 3 in the 2—100 μg/L.The method detection limit is 10 μg/kg,and it can be meet all the requirements of national residues level.