The method of ultra performance liquid chromatography-tandem mass spectrometry / mass spectrometry was established to detect medroxyprogesterone acetate residues in beef.The sample was hydrolyzed by β-glucuronidase in pH 5.2 buffer and the enzymatic hydrolysis time was 12h.The sample was extracted with methanol-water solution, enriched and purified through solid phase extraction column and concentrated to a definite volume.Methanol and 0.1% formic acid water were used as mobile phase to conduct gradient elution.The sample was separated by ACQUITY UPLC BEH C18 column.The positive electrospray ionization (ESI+) mode and multiple reactions monitoring (MRM) were adopted to detect, and internal standard method was used for quantitative determination.The method was accurate, stability and high sensitive.The linear relationship was well in range of 0.64~50.95μg/L, and the correlation coefficient ? reached 0.999.The addition amount range of 0.25~2.50μg/L of blank sample, medroxyprogesterone acetate recovery rate was 95.3%~108.6% and relative standard deviation was 5.6%.The detection line of this method was 0.07μg/kg and quantitative detection limit was 0.25μg/kg.%建立了超高效液相色谱-串联质谱/质谱测定牛肉中甲羟孕酮乙酸酯的方法.试样在pH值为5.2的缓冲液内用β-葡萄糖醛酸酶酶解12h,用甲醇-水溶液提取,经固相萃取富集净化,浓缩定容,以甲醇和0.1%甲酸水为流动相进行梯度洗脱,用ACQUITY UPLC BEH C18柱分离,采用电喷雾正离子(ESI+)模式,多反应监测(MRM)进行检测,内标法定量测定.该方法准确、稳定、灵敏度高.在0.64~50.95μg/L浓度范围内线性关系良好,相关系数?达0.999,空白样品在0.25~2.50μg/L的添加范围内,甲羟孕酮乙酸酯的回收率为95.3%~108.6%,相对标准偏差为5.6%,本方法的检测线为0.07 μg/kg,定量检出限为0.25μg/kg.
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