亚甲基蓝分光光度法测定废水硫化物的不确定度评定研究

Uncertainty in Determining Sulfide in Wastewater by Methylene Blue Spectrophotometry

分析了应用亚甲基蓝分光光度(GB/T16489-1996)测定废水硫化物测试过程中不确定度影响因素,主要来源为硫化物标准溶液、标准曲线拟合、随机效应、分光光度计和取样体积这五部分。本测量合成相对标准不确定度0.025 9;其中由测定样品质量引入的不确定度为0.024 7;由样品体积引入的不确定度为0.007 7。本次废水中硫化物测量结果为:0.110±0.006 mg/L,k=2(包含概率约为95%)。

This paper studied on the influencing factors in determining sulfide in wastewater using methylene blue spectropho- tometry（ GB/T 16489 - 1996）. Its main factors are sulfide standard solution, standard curve fitting, random effects, spectropho- tometer and sampling volume. The uncertainty standard is 0. 025 9, while the uncertainty introduced by the determination of the sample quality is 0. 024 7 and uncertainty introduced by sample volume is 0. 007 7. The measurement result of the wastewater sul- fide is 0. 110 μ0. 006 mg / L, k = 2（probability about 95% ）.