靛酚蓝分光光度法测定公共场所空气中氨的不确定度评定

Uncertainty Evaluation of Determination of Ammonia in the Air in Public Places with Indophenol Blue Spectrophotometric

分析了应用靛酚蓝分光光度法(GB/T18204.25-2000)测试公共场所空气氨过程中不确定度的影响因素,其主要来源为标准溶液、标准曲线拟合、样品重复测定、分光光度计、取吸收液体积和采集气样标况体积这六部分引入的不确定度。相对合成不确定度为4.89%;其中采样部分引起的相对不确定度为1.2%;吸收液中待测物质量引起的相对不确定度为4.74%。最大的相对不确定度分量,是标准曲线拟舍引起的相对不确定度为4.17%;其次是样品重复测定引入不确定度为1.7%。本次测量结果为:0.346±0.034mg/3,k=2。(约95%置信水平)

The paper analyses influnce factors of uncertainty in the process of determining ammonia in public places with indophenol blue spectrophotometry GB/T18204.25-2000. The main influnce factors are standard solution,standard curve fitting,sample repeated measurements,spectroscopic photometer,absorption liquid volume and standard volume of gas samples. Relative combined uncertainty is 4.89%, where the the relative uncertainty caused by sampling part is 1.2%and the relative uncertainty caused by absorption of liquid analyte mass is 4.74%. The largest relative uncertainty component is caused by the relative standard curve fitting of 4.17%;followed by repeated measurements of sample introduction uncertainty of 1.7%. The measurement result is:0.346 ± 0.034mg/m3,k=2. (Approximately 95%confidence level) .