DPD分光光度法测定水中游离氯的不确定度评定

目的]建立分光光度法测定水中游离氯的不确定度评定方法。方法]根据HJ 586—2010规定的检测方法,对DPD分光光度法测定水中游离氯进行了不确定度评定。对测量不确定度分量的来源,包括标准物质、标准溶液配制和稀释过程、测量重复性、标准曲线线性拟合等进行分析。最后计算了合成不确定度和扩展不确定度。结果]曲线线性拟合引入的不确定度对合成不确定度贡献最大,其次为测量重复性和标准系列溶液配制引入的不确定度,标准贮备液引入的不确定度分量贡献最小,可忽略不计。结论]该研究可为准确测定水中游离氯含量提供理论支持。

Uncertainty Evaluation of Measuring Free Chlorine in Water by DPD Spectrophotometry

Objective]To establish an evaluation method for uncertainty in spectrophotometry determination of free chlorine in water.Meth-od]Based on the detection method of HJ 586—2010, the uncertainty of free chlorine measuring in water by DPD spectrophotometry was evalu-ated.The main sources of uncertainty including preparation of standard solution, repetition of measurement, and linear fitting of standard curve were analyze.Finaly, the combined and expanded uncertainty was calculated.Result]The results showed that linear fitting of standard curve had the maximum contribution to the uncertainty, the repetition of measurement and preparation of standard solution was following, the stand-ard stock solution had the minimum contribution and can be neglected. Conclusion] The study can provide theoretical support for accuracy de-termination free chlorine in water.