液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度评定

Uncertainty evaluation of determination of dexamethasone in milk by high performance liquid chromatography-tandem mass spectrometry

目的评定液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度。方法样品经过固相萃取柱净化处理后,经色谱柱分离,流动相等度洗脱,多反应监测模式进行检测。依据JJF10591.1-2012《测量不确定度评定与表示》,考察称量、标准溶液配制、标准曲线拟合、测量重复性等主要因素引入的不确定度,幵对不确定度的各分量进行计算和合成。结果当牛奶中地塞米松添加量为3.67μg/kg时,在95%的置信区间下,其扩展不确定度为0.198μg/kg(k=2)。评定结果表明,实验过程的不确定度主要来源于曲线拟合、测量的重复性。结论该斱法准确可靠,适用于液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度评定,对检测结果准确度的提高具有指导意义。

Objective To evaluate the uncertainty of determination of dexamethasone in milk by high performance liquid chromatography-tandem mass spectrometry.Methods The samples were purified by solid phase extraction column,separated by chromatographic column,eluded by flow equality,and detected by mu lti-reaction monitoring model.According to JJF 1059.1-2012 Measurement uncertainty evaluation and presentation,the uncertainty of main factors such as weighing,standard solution preparation,standard curve fitting,and repeatability measurement were investigated,and the components of uncertainty were calculated and synthesized.Results When the content of dexamethasone in milk was 3.67 μg/kg,the extended uncertainty was 0.198 μg/kg（k=2） under the 95% confidence interval.The evaluation results showed that the uncertainties of the experiment were mainly derived from curve fitting and measurement repeatability.Conclusion The evaluation method is accurate and reliable,which is suitable for the evaluation of uncertainty of determination of dexamethasone in milk by high performance liquid chromatography-tandem mass spectrometry.It is instructive to improve the accuracy of test results.