UPLC-MS/MS法测定生菜中吗啉胍含量及不确定度评价

Determination of Morpholine Residues in Lettuces by UPLC-MS/MS and Its Uncertainty Evaluation

建立超高效液相色谱串联质谱法(ultra performance liquid chromatography-tandem massspectrometry,UPLC-MS/MS)测定生菜中吗啉胍残留量的分析方法并进行不确定度评价。样品经提取净化后,通过电喷雾离子源正离子扫描、多反应监测模式(MRM)对吗啉胍进行定量分析。通过建立数学模型,分析测量不确定度来源,并量化各不确定度分量,合成不确定度。吗啉胍在0.1~20 mg/L范围内呈良好线性,R^(2)为0.9993,在0.5、5.0和10.0μg/kg这3个水平的加标回收率为84.08%~98.06%(n=6),相对标准偏差为3.58%~5.26%(n=6)。样品中吗啉胍含量测定结果为17.5μg/kg时,在95%置信区间下,扩展不确定度为2.84μg/kg(k=2)。该方法前处理快速高效、准确度高、重现性好,回收率及精密度均能达到实验要求,不确定度主要由标准溶液、标准曲线的建立及样品加标回收引起。实验结果可为UPLC-MS/MS法测定生菜中吗啉胍残留量及不确定度评价提供参考。

To establish a method for the determination of morpholine guanidine residues in lettuce,ultra performance liquid chromatography-tandem mass spectrometry and uncertainty evaluation of the established method were studied.After samples were extracted and purified,the morpholine guanidine was quantified by scanning with positive ions from an electrospray ionization source in multiple reaction monitoring mode.The uncertainty was synthesized by building a mathematical model to analyze the sources of measurement uncertainty and quantify each uncertainty component.The morpholinoguanidine showed a good line in the range of 0.1~20 mg/L with a correlation coefficient R^(2) of 0.9993.The spiked recoveries at the three levels of 0.5,5.0 and 10.0μg/kg ranged from 84.08%to 98.06%(n=6)with the relative standard deviations of 3.58%to 5.26%(n=6),and the extended uncertainty was 2.84μg/kg(k=2)at 95%confidence interval for the determination of morpholine guanidine in the sample at 17.5μg/kg.The method was rapid and efficient,highly accurate and reproducible,and the recovery and precision can meet the test requirements.The uncertainty was mainly caused by the standard solution,the establishment of the standard curve and the recovery of the sample spiking.The experimental results could provide a reference for the determination of morpholine guanidine residues in lettuce by UPLC-MS/MS and the uncertainty evaluation.