改进五步碘量法测定二氧化氯含量的研究

STUDY ON MEASUREMENT OF CHLORINE DIOXIDE CONTENT BY MODIFIED FIVE-STEP IODOMETRY

在实验室用“五步碘量法”测定两种二氧化氯产品含量,以了解影响该方法测定准确性的因素并进行改进。结果,按规范所示方法(方法1)进行测定,消毒剂A中二氧化氯含量为1939.34mg/L,消毒剂B中二氧化氯含量为1053.94mg/L。对方法1的反应液的pH值进行适当调节控制(方法2)后再测定,则消毒剂A中二氧化氯含量为7042.90mg/L,消毒剂B中二氧化氯含量为2459.11mg/L。显示方法1与方法2测定结果差异较大。说明五步法测定过程中根据不同产品pH值作适当调节,使pH值均能接近7,才能保持二氧化氯最佳反应状态,所测得的二氧化氯含量比较接近实际。

The content of two chlorine dioxide products was measured with 'five-step iodometry' in laboratory in order to know the factors influencing the accuracy of measurement by this method and to improve it. Results: Measurement was carried out according to the method(method 1) specified in the 'Disinfection Technical Guidelines' and the results showed that the chlorine dioxide content in disinfectant A was 1939.34 mg/L and that in disinfectant B was 1053.94 mg/L. Measurement was performed again after the pH value of the reaction solution in method 1 was regulated appropriately (method 2), and found that the chlorine dioxide content in disinfectant A was 7042.90 mg/L and that in disinfectant B was 2459.11 mg/L. It was showed that the results of measurement by method 1 and method 2 differed considerably, indicating that the pH value in the course of measurement by five-step method should be regulated according to different products to make the pH value approximate to 7, only at which the chlorine dioxide can be kept at optimal reactive state and the chlorine dioxide content measured can approximate the actual value.