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目的对液相色谱-串联质谱法测定婴儿奶粉中的三聚氰胺的不确定度进行评估。方法以GB/T22388-2008《原料乳与乳制品中三聚氰胺检测方法》为基础改良方法,测定婴儿奶粉中的三聚氰胺。依据CNAS-GL06:2006《化学分析中不确定度的评估指南》,通过数学建模建立不确定度来源鱼骨图,分析不确定度来源并计算不确定度分量。结果当奶粉中的三聚氰胺残留量为50μg/kg时,测量不确定度为3.70μg/kg(k=2),其中液质仪器校准、重现性和偏差对不确定度影响最大。结论内标法的线性拟合对测量不确定度贡献较小,对三聚氰胺的常规检测具有重要意义。
Objective To evaluate the uncertainty of melamine in infant formula by liquid chromatography-tandem mass spectrometry. Methods Based on the improved method of GB / T22388-2008 “Melamine in raw milk and dairy products”, the melamine in infant formula was determined. According to the CNAS-GL06: 2006 Guidance on Evaluation of Uncertainty in Chemical Analysis, a mathematical model was used to establish the fishbone diagram of the source of uncertainty, and the source of uncertainty was analyzed to calculate the components of uncertainty. Results When the residual amount of melamine in milk powder was 50μg / kg, the uncertainty of measurement was 3.70μg / kg (k = 2). The calibration, repeatability and deviation of LCM had the greatest impact on the uncertainty. Conclusion The linear fitting of the internal standard method has little contribution to the measurement uncertainty and is of great significance for routine testing of melamine.