[目的]研究羊奶粉中氯霉素、甲砜霉素、氟甲砜霉素残留的液相色谱-串联质谱测定方法。[方法]样品经乙腈提取,固相萃取柱净化,以甲醇水作为流动相,采用多反应监测负离子模式进行定性及内标法定量分析。[结果]氯霉素、甲砜霉素、氟甲砜霉素的相关系数均大于0.999,氯霉素检出限为0.1 µg/kg,甲砜霉素和氟甲砜霉素检出限为0.2 µg/kg;氯霉素加标回收率为100.9%~116.2%,甲砜霉素加标回收率为88.4%~99.6%,氟甲砜霉素加标回收率为89.6%~103.2%。[结论]该方法灵敏度高、准确性好,适于测定羊奶粉中氯霉素、甲砜霉素,氟甲砜霉素的残留量。

[Objective]A method for the determination of chloramphenicol,thiamphenicol and florfenicol residues in sheep milk powder by liquid chromatography-tandem mass spectrometry was studied.[Method]The samples were extracted by acetonitrile,purified by solid phase extraction column,and analyzed qualitatively and quantitatively by internal standard method with methanol and water as mobile phase.[Result]The correlation coefficients of chloramphenicol,thiamphenicol and florfenicol were greater than 0.999,the detection limit of chloramphenicol was 0.1 µg/kg,and the detection limit of thiamphenicol and florfenicol was 0.2 µg/kg.The recovery rate of chloramphenicol was 100.9%~116.2%,the recovery rate of thifomycin was 88.4%~99.6%,and the recovery rate of florfenicol was 89.6%~103.2%.[Conclusion]The method has high sensitivity and accuracy,and is suitable for the determination of chloramphenicol,thiamphenicol and florfenicol residues in sheep milk powder.