水杨酸分光光度法测定水中氨氮的测量不确定度评定

应用测量不确定度评定理论,结合水杨酸分光光度法对水中氨氮测量不确定度进行全面分析,找出其影响不确定因素并对不确定度进行评估,实验分析表明水杨酸分光光度法测定水中氨氮含量为1.44 mg/L的样品,其扩展不确定度为0.054 mg/L,影响不确定度最大的主要分量是样品重复性测量引入的不确定度,同时,提高量器精密度也是降低不确定度的有效方法。

Assessment Evaluation on Measurement Determined by Spectrophotometry Uncertainty of NH3 - N in Water Method with Salicylic Acid

Using the theory of measurement uncertainty evaluation and combining with the spectrophotometry method with salicylic acid, a comprehensive analysis of measurement uncertainty of NH3 - N in water was made to find its influential factors of uncertainty and to evaluate the uncertainty. Experimental analysis showed that the content of NH3 - N in water of the sample determined by spectrophotometry method with salicylic acid was 1.44 mg/L, its expanded uncertainty was 0. 054 mg/L, the main sources of uncertainty come from pre - processing step of samples, and one of effective wavs to reduce the measurement uncertainty promoted the accuracy of measuring vessel.