液相色谱-电感耦合等离子体质谱法测定大米中无机砷的不确定度评估

Uncertainty evaluation of determination of inorganic arsenic in rice by liquid chromatography inductively coupled plasma mass spectrometry

中文关键词:  液相色谱-电感耦合等离子体质谱法  大米  无机砷  不确定度

英文关键词:liquid chromatography inductively coupled plasma mass spectrometry  rice  inorganic arsenic  uncertainty

中文摘要:

      目的 评估液相色谱-电感耦合等离子体质谱法(liquid chromatography inductively coupled plasma mass spectrometry, LC-ICPMS)测定大米中无机砷的不确定度。方法 采用LC-ICPMS测定大米中AsⅢ和AsⅤ含量, 建立数学模型, 并从测量重复性、样品称量、提取液移取体积、标准溶液配制、标准曲线拟合等方面进行测量不确定度的计算。结果 大米样品中AsⅢ、AsⅤ、i-As的含量分别为0.180、0.014、0.194 mg/kg, 在95%的置信区间下,其扩展不确定度为0.003、0.002、0.028 mg/kg, k=2。结论 测量过程中的不确定度主要来源于测量的重复性、标准溶液的配制和曲线拟合, 需要在测量过程中加以注意。

英文摘要:

      Objective To evaluate the uncertainty for determination of inorganic arsenic in rice by liquid chromatography inductively coupled plasma mass spectrometry(LC-ICPMS). Methods The contents of AsⅢ and AsⅤ in rice was determined by LC-ICPMS. The mathematical model was established and the measurement uncertainty from the measurement repeatability, sample weighing, extraction volume, standard solution preparation and standard curve fitting, etc was calculated. Results When the content of AsⅢ, AsⅤand i-As in rice samples were 0.180, 0.014 and 0.194 mg/kg, the expanded uncertainty was 0.003, 0.002 and 0.028 mg/kg respectively(k=2) under the 95% confidence interval. Conclusion The uncertainty in the measurement process mainly comes from the repeatability of measurement, the preparation of standard solution and curve fitting, which should be paid attention to in the measurement process.