LC-MS/MS法测定动物源性食品中三甲氧芐氨嘧啶残留量的不确定度评估

Uncertainty evaluation of the determination of trimethoprim residues in animal-derived foods by LC-MS/MS

采用液相色谱-串联质谱法(LC-MS/MS)对猪肉中的三甲氧芐氨嘧啶残留量进行分析。按照SN/T 2538—2010《进出口动物源性食品中二甲氧苄氨嘧啶、三甲氧苄氨嘧啶和二甲氧甲基苄氨嘧啶残留量的检测方法液相色谱-质谱/质谱法》测定猪肉中三甲氧芐氨嘧啶残留量的含量,以CNAS-GL006—2019《化学分析中不确定度的评估指南》和JJF 1059.1—2012《测量不确定度评定与表示》的要求和方法为参照,对整个实验过程中的不确定度因素进行系统分析,计算不确定度分量和扩展不确定度。所测猪肉中三甲氧苄氨嘧啶残留量的含量为14.29μg/kg,置信概率为95%时,测定结果中合成不确定度为0.74μg/kg,扩展不确定度为1.48μg/kg(k=2)。结果表明,液相色谱串联质谱仪的校准和标准溶液是猪肉中三甲氧苄氨嘧啶残留量测量不确定度的主要来源。

The analysis and evaluation of trimethoprim residues in pork using liquid chromatography-tandem mass spectrometry(LC-MS/MS).According to SN/T 2538-2010"Detection method for the determination of dixyrazine,trimethoprim and doxycycline residues in animal-derived food products for import and export:Liquid chromatography-mass spectrometry(LC-MS/MS)",the content of trimethoprim residues in pork is determined.With reference to CNAS-GL006-2019"Guidance for the evaluation of uncertainty in chemical analysis"and JJF 1059.1—2012"Evaluation and expression of measurement uncertainty",the uncertainty factors in the whole experimental process are systematically analyzed,and the uncertainty components and expanded uncertainty are calculated.The measured trimethoprim residue content in pork was 14.29μg/kg,and the combined uncertainty in the measurement result was 0.74μg/kg with a confidence probability of 95%,and the expanded uncertainty was 1.48μg/kg(k=2).The results indicate that calibration of liquid chromatography tandem mass spectrometer and standard solution are the main sources of uncertainty in the measurement of trimethoprim residues in pork.