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 14.29 μg/kg,and the combined uncertainty in the measurement result was 0.74 μg/kg with a confidence probability of 95％,and the expanded uncertainty was 1.48 μg/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.
万方数据