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目的评定原子荧光光度法测定人体尿液中砷的测量不确定度。方法结合实际日常检测工作,评价原子荧光光度法测定尿中砷的测量不确定度,建立数学模型,查找该试验过程中测量不确定度来源,分析标准物质溶液转移、稀释定容、样品的前处理、曲线拟合以及仪器等影响不确定度的分量。结果影响样品结果合成不确定度的主要分量是样品的前处理,该方法测定尿中砷的含量为(9.17±0.59)μg/L,k=2;标准溶液浓度、样品消解处理、样品加标回收率、标准曲线拟合、原子荧光光度计和尿液比重计的不确度的分量分别为0.62%、2.80%、0.69%、0.94%、0.30%和0.40%,根据各个分量计算出此方法的合成不确定度为3.20%,扩展不确定度U为6.40%。结论在实际工作中必须严格控制好样品前处理的各个步骤,并按照仪器的操作规程进行测定。
Objective To assess the uncertainty of measurement of arsenic in human urine by atomic fluorescence spectrometry. Methods Combined with the actual daily testing work, the uncertainty of measurement of arsenic in urine was evaluated by atomic fluorescence spectrophotometry. The mathematical model was established to find the sources of measurement uncertainty during the test. The standard solution was analyzed for solution transfer, dilution and volume determination, Processing, curve fitting, and other components that affect the uncertainty. Results The main component affecting the uncertainty in the synthesis of the sample was the pretreatment of the sample. The determination of arsenic in urine was (9.17 ± 0.59) μg / L, k = 2. The standard solution concentration, sample digestion, The recovery, standard curve fit, atomic fluorescence photometer and urinalysis were 0.62%, 2.80%, 0.69%, 0.94%, 0.30% and 0.40%, respectively. The method was calculated according to each component The synthetic uncertainty is 3.20%, and the expanded uncertainty U is 6.40%. Conclusion In practical work, we must strictly control the various steps of sample preparation and determine according to the instrument’s operating rules.