超高效液相色谱-串联质谱法测定牛奶中土霉素残留的不确定度评估

Uncertainty evaluation of oxytetracycline in liquid milk by ultra performance liquid chromatography-tandem mass spectrometry

目的采用超高效液相色谱-串联质谱法对牛奶中土霉素残留的不确定度进行评估。方法测定牛奶中的土霉素,建立该方法测定牛奶中土霉素含量不确定度的数学模型,确定不确定度来源并对其评定。结果当牛奶中土霉素含量为0.049μg/g时,其扩展不确定度为0.0036μg/g(k=2)。其中,测量重复性和标准曲线对不确定度的影响最大。结论采用超高效液相色谱-串联质谱法测定牛奶中土霉素含量应严格控制实验条件,保证实验具有良好的重复性,另外还要保证标准曲线具有良好的线性。

Objective To establish a mathematical model of uncertainty evaluation for the determina-tion results of oxytetracycline in liquid milk by ultra performance liquid chromatography-tandem mass spec-trometry method. Methods The sources of uncertainty of the whole determination procedure were analyzed and the combined uncertainty was finally obtained. Results The expanded uncertainty of 0.0036μg/g (k=2) with 0.049 μg/g of the content of oxytetracycline was derived. The major sources of uncertainty of mea-surement included the repeatability of detection and the curve fitting. Conclusion It is necessary to control experimental conditions and the linear of standard curve to make sure the testing results are accurate.