为解决GB/T 5750.11-2006生活饮用水标准检验方法中的3，3’，5，5’-四甲基联苯胺（TMB）目视比色法检测余氯时出现的评价方法准确性欠佳、TMB显色剂发黄、显色体系偏绿等问题，对TMB目视比色法的评价方法、TMB显色剂的配制条件和水样的检测条件进行了研究。结果表明，次氯酸钠不宜作为余氯标准物质来评价TMB目视比色法的改进效果，而通过检测显色体系的A450和目视比色值相结合的方法来判断方法改进效果更为准确。采用优级纯浓盐酸和无氯纯水室温搅拌溶解，可使显色剂无色透明，从而解决TMB显色剂发黄的问题，符合国标要求。将显色剂配制用酸（盐酸）的浓度由国标中0.1 mol/L变更为0.6 mol/L，可解决余氯显色体系偏绿的问题。显色体系pH变化后，显色时间、显色温度、显色剂用量可仍按照国标方法的要求进行操作。通过以上改进措施，进一步提高了余氯检测结果的准确度。%In order to solve problems of TMB visual colorimetry, such as poor accuracy of evaluation method of improved testing method, yellow color of TMB solution and partial green color of color system in GB/T 5750.11-2006 in determination of residual chloride in water,improved evaluation method, preparation conditions of TMB chromogenic agent and testing conditions of residual chlorine water were researched. Results showed that sodium hypochlorite should not be used as standard substance to evaluate the improving effect of TMB visual colorimetry, evaluating by A450 and visual colorimetric value of chromogenic system was more accurate. Preparing TMB chromogenic agent with hydrochloric acid(GR)and pure water without residual chlorine at room temperature could make chromogenic agent colorless and transparent, solve the problem of yellow color of TMB solution, conform to requirements of GB/T 5750.11-2006. It could solve the problem of partial green color of color system by changing the concentration of hydrochloric acid, which was used to prepare TMB solution, from 0.1 mol/L to 0.6 mol/L, while chromogenic time, color temperature and dosage of chromogenic agent still could be operated according to requirements of national standard. Accuracy of testing results of residual chlorine was further improved through above measures.
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