纯水中痕量氯离子快速检测方法

Method of Quick Determination of Trace Chloride Ions in Pure Water

纯水是锅炉的换热介质,水中的氯离子即使是痕量级的存在,也能造成金属组织的晶间裂纹与脆性破裂,对奥氏体不锈钢造成应力腐蚀,因此纯水中氯离子含量是重要的监控指标。目前氯离子的测定常采用硝酸银容量法、离子选择电极法和离子色谱法(IC)等,但因各种原因难以满足快速检测的需要。该文介绍了采用便携式数字滴定仪替代常规滴定管的方法,根据国标《汞盐滴定法》分析方法对纯水中氯离子快速测定的要求,在实验的基础上归纳了氯离子含量小于1.0 mg/L的范围读数与含量的关系。经实验室研究验证,其精确度、准确度和最低检测限都满足要求,能适用于纯水中低浓度氯离子的快速检测。

Pure water is the media of heat exchange in the boiler. Even existing in trace amount, chloride ion in the pure water can cause crack among metal crystalline solid and brittleness break, it can also cause stress corrosion of austenitic stainless steel. So the concentration of chloride ion is an important index in pure water quality control. At present, the common methods for determina- tion of chloride ion include silver nitrate titration, ion selective electrode and ion chromatography （IC）, etc, but they were not fulfilled the need of quick determination due to various reasons. The paper introduces a method with portable digital titrator which take palce of common titration for quick determing chloride ion in pure water. The results show that the accuracy, precision and minimum detec- tion limit all fulfill the need of quick determination of low conncentration of chloride ion in pure water.