高效液相色谱串联质谱法快速测定牛奶中地塞米松残留量

Rapid determination of dexamethasone residues in milk by high performance liquid chromatography tandem mass spectrometry

目的建立高效液相色谱串联质谱法快速有效检测牛奶中地塞米松残留量的分析方法。方法样品经乙腈提取,正己烷萃取去除杂质后,取乙腈层旋转蒸发至近干,用20%乙腈水溶液溶解后,经C18色谱柱分离,以甲醇-水(9:1,V:V)为流动相,应用高效液相色谱串联质谱仪在电喷雾负离子模式(electron spray ionization,ESI-)下采用多反应监测(multiple reaction monitoring,MRM)方式对牛奶中地塞米松进行定性及定量分析。结果地塞米松在5~100 ng/mL范围内呈良好的线性关系,方法检出限为0.19μg/kg(S/N=3),不同水平的加标回收率在85%~107.2%之间,相对标准偏差在0.84%~1.22%之间(n=3)。结论该方法具有快速、简便、准确、灵敏的特点,适用于牛奶中地塞米松残留量的分析检测,可用于日常大批量快速筛查工作,有效提高日常工作效率。

Objective To establish a rapid and effective method for the determination of dexamethasone in milk by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).Methods Dexamethasone in milk were extracted by acetonitrile and purified by n-hexane,then take acetonitrile layer and rotate to evaporate to near dry,disolved by 20%acetonitrile aqueous solution and separated by C18 column,used methanol-water(9:1,V:V)as mobile phase and detecte qualitative and quantitative by HPLC-MS/MS under electronic spray ionization with an electrospray ionization source in the negative ion(ESI-)detection mode by multiple reaction monitoring(MRM)scanning.Results There was a good linear relationship in the range of 5-100 ng/mL.The detection limit of the method was 0.19μg/kg(S/N=3).The average recovery was 85%-107.2%,and the relative standard deviation(RSD)was 0.84%-1.22%(n=3).Conclusion It is such a rapid,simple,accurate and sensitive method that can be used in the determination of dexamethasone in milk and daily mass rapid scanning to improve daily work efficiency effectively.