超高效液相色谱-串联质谱法测定豆芽中甲硝唑及羟基甲硝唑残留量的不确定度评定

Uncertainty evaluation for determination of metronidazole and hydroxym etronidazole residues in bean sprouts by ultra performance liquid chromatography-tandem mass spectrometry

目的评定分析超高效液相色谱-串联质谱法(ultra performance liquid chromatography tandem mass spectrometry,UPLC-MS/MS)测定豆芽中甲硝唑以及羟基甲硝唑的残留量的不确定度。方法试样经乙酸乙酯提取2次,旋转蒸发,混合阳离子交换柱净化,经Infinity Lab Poroshell SB-Aq色谱柱分离,采用UPLC-MS/MS检测,内标法进行定量分析。结果标准曲线拟合以及标准溶液配制产生的不确定度分量最大,当豆芽中甲硝唑含量为10.1μg/kg时,其扩展不确定度U=2.1μg/kg(k=2);当豆芽中羟基甲硝唑含量为10.3μg/kg时,其扩展不确定度U=1.7μg/kg(k=2)。结论豆芽中不确定度最主要来源于标准曲线的拟合以及标准溶液的配制过程,其次是回收率,其他因素的影响较小。

Objective To evaluate the uncertainty of determination the residues of metronidazole and hydroxy metronidazole residues in bean sprouts by ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).Methods The samples were extracted by ethyl acetate for twice,then purified by rotating evaporation and mixed cation exchange column.The samples were separated by Infinity Lab Poroshell SB-Aq column,detected by UPLC-MS/MS,and quantitatively analyzed by internal standard method.Results Standard curve fitting and standard solution preparation produced the largest uncertainty component.When the metronidazole content in bean sprouts was 10.1μg/kg,the expanded uncertainty U=2.1μg/kg(k=2).When the content of hydroxy metronidazole in bean sprouts was 10.3μg/kg,the expansion uncertainty U=1.7μg/kg(k=2).Conclusion The uncertainty of bean sprouts is mainly derived from the fitting of standard curve and the configuration of standard solution,followed by the recovery rate,and other factors have little influence.