电感耦合等离子体质谱法测定扇贝中铅、砷、镉含量的不确定度评定

目的评定采用电感耦合等离子体质谱法(inductively coupled plasma-mass spectrometry,ICP-MS)检测扇贝中铅、砷、镉含量的不确定度。方法分析整个测量过程中存在的不确定度因素,包括测量重复性、称样量、稀释体积、标准溶液、标准曲线拟合以及方法回收率等,建立数学模型,对测量结果的不确定度进行评定。结果影响测量结果的不确定度主要来源于测量重复性、样品前处理和标准曲线拟合。扇贝样品中结果表示分别为:铅含量(1.82±0.33)mg/kg;砷含量为(3.43±0.35)mg/kg;镉含量为(1.32±0.17)mg/kg,k=2。结论该方法准确度高,适用于扇贝中重金属元素的检测,为提高数据准确性提供有效指导。

Uncertainty evaluation for determination of lead, arsenic and cadmium in scallop by inductively coupled plasma-mass spectrometry

Objective To evaluate the uncertainty of determination of lead, arsenic and cadmium content in scallops by inductively coupled plasma-mass spectrometry. Methods The uncertainty factors in the whole measurement process were analyzed, such as the repeatability of samples, sample volume, dilution volume, standard solution, standard curve fitting and method recovery rate. The mathematical model of uncertainty evaluation was established for evaluating the uncertainty of measurement results. Results The uncertainties affecting the measurement results mainly came from measurement repeatability, sample preparation and standard curve fitting. The results of the scallop samples were as follows: lead content was (1.82±0.33) mg/kg, arsenic content was (3.43±0.35) mg/kg, cadmium content was (1.32±0.17) mg/kg (k=2). Conclusion This method has high accuracy and is suitable for detecting heavy metal elements in scallops, and which can provide effective guidance for improving data accuracy.