低电导率标准溶液的研制-仪器仪表工程专业论文.docxVIP

中文摘要 电导率是评判水质状况好坏与否的一个重要物理量，如今军事、医药、化工、 电站、电子、食品饮料等行业在用水方面都有较高的要求，因此对上述行业的用 水进行电导率值准确的监控和测量尤为重要。 用电导率仪是目前测量电解质溶液电导率最便捷快速的手段，不论在工业生 产还是实验分析中都有着广泛的应用。对电导率仪进行量值溯源就必须通过用电 导率标准溶液对该仪器校准来实现，然而电导率标准溶液在不同浓度下的电导率 值并非呈线性关系，所以最有效和直接的方法就是采用尽可能接近待测样品电导 率值的电导率标准溶液来校准。但目前国内已有的氯化钾电导率标准物质的电导 率值仍然相对较高，最低的也有 84μs/cm(25℃)，所以用其校准的电导率仪对纯 水或超纯水等低电导率值测定的准确度偏差还很大，测量结果的不确定度无法估 算。 本文通过研究非水溶剂对溶液电导率值的影响，确定了低电导率标准溶液的 配方，并配合国内已有的电导率值为 1408.3μs/cm(25℃)的国家二级标准物质 GBW(E)130281 氯化钾电导率标准物质，制备了一种以正丙醇-水混合物为溶剂 的低电导率标准溶液，其电导率值可以达到 17.7μs/cm(25℃)，适用于对电导率仪 在其低量程(0~20) μs/cm 范围内的校准，并对该溶液的稳定性、均匀性以及不确 定度做了检验和评价。可以为使用电导率计量仪器的各行各业在生产或研发过程 中低量程的定量控制起到更大的帮助。 关键词：电解质电导率；标准溶液；不确定度；非水溶剂 ABSTRACT Conductivity is an important physical quantity to judge the water quality. Now the requirement of water quality in Military, medicine, chemical industry, power plants, electronics, Food Beverage industries is much high. Therefore, it is particularly important to have an accurate monitoring and control of the conductivity of water that they use. The most convenient and rapid way to measuring the conductivity of electrolyte solutions is by means of using conductivity meter which has been widely applied in industrial production or experimental analysis. Traceability is achieved by using conductivity standard solutions to calibrate conductivity meter. However the conductivity value of different concentrations of conductivity standard solutions is not linear, so the most effective and direct way to calibrate conductivity meter is to choose a conductivity standard solution whose value is as close as possible to that of sample. But in our country, the lowest value of conductivity standard solution is 84μs/cm(25℃) which is still relatively high. Therefore, it still has a large deviation by using it to calibrate the conductivity meters. Even the uncertainty of measurement results cannot be estimated. In this paper, by researching the affect of non-aqueous solvent on solution conductivity, the formulation of the low conductivity sta