液相色谱串联质谱法测定有机肥料中磺胺甲噻二唑残留量的不确定度评定

Uncertainty evaluation for the determination of sulfamethizole residues in organic fertilizers by liquid chromatography-tandem mass spectrometry method

依据《有机肥料中19种兽药残留量的测定液相色谱串联质谱法》(GB/T 40462—2021)对有机肥料中磺胺甲噻二唑(SMT)的残留量进行测定,对测量结果进行不确定度评定。不确定度来源包括标准溶液配制、样品制备、测量重复性、回收率及仪器等分量。相对标准不确定度计算结果表明标准曲线拟合、标准物质纯度和标准曲线配制是影响不确定度的主要因素,应在实际试验过程中加以重点关注与控制。在95%置信水平下,取扩展因子k=2,待测肥料样品中最终结果表示为:X(SMT)=(189.82±20.12)mg/kg。

The sulfamethizole residues in organic fertilizers were determined according to“Determination of 19 veterinary medicines in organic fertilizer-Liquid chromatography-tandem mass spectrometry method”(GB/T 40462—2021),and the uncertainty was evaluated.The sources of uncertainty included the components of standard solution preparation,sample preparation,measurement repeatability,recovery and instrument.The calculation results of relative standard uncertainty indicated that the main factors affecting the uncertainty were the fitting of the standard curve,the purity of the standard and the preparation process of the standard curve,which should be focused and controlled during the actual experiment.It was found that at the 95%confidence level,the final result in the fertilizer sample was expressed as X(SMT)=(189.82±20.12)mg/kg when the expansion factor(k)was taken as 2.