五步碘量法测定二氧化氯含量的影响因素研究

STUDY ON THE INFLUENCING FACTORS OF FIVE-STEP IODOMETRY FOR CHLORINE DIOXIDE MEASUREMENT

目的研究五步碘量法测定消毒剂二氧化氯含量的影响因素,以提高检测的准确性。方法通过科学选择试剂及限定用量,重新确定氮气吹气压力与时间,达到检测的精确度和准确性。限定磷酸盐缓冲液和硫酸溶液用量为10 ml,明确高纯氮气吹气压力为0.06 MPa和吹气时间为20 min。结果采用2 mol/L硫酸溶液代替2.5 mol/L的盐酸溶液,限定磷酸盐缓冲液和硫酸溶液用量等改进措施,使得改良后五步碘量法可直接测定二氧化氯浓度在5~2 500 mg/L范围的消毒液样品液,取样量为1~20 ml,相对标准偏差为0.70%。结论本研究发现试剂种类和用量以及氮气吹气压力等因素影响五步碘量法测定二氧化氯的准确性,经过改良,取得更准确的测定结果。

Objective To study the influence factors of five - step iodometry for chlorine dioxide in disinfectants meas- urement, in order to improve the accuracy. Methods By scientific reagent selection and dosage limitation, the blowing ni- trogen pressure and time were determined, so as to reach the accuracy of detection. The dosage of phosphate buffer and the sulfuric acid was 10 ml, the time of blowing nitrogen was 20 rain with the pressure was O. 06 MPa. Results By the impro- ving measure of using the sulfuric acid concentration of 2 mol/L instead of the hydrochloric acid concentration of 2.5 mol/L, limiting the dosage of PBS and sulphuric acid, we could measure the disinfectant with the chlorine dioxide con- centration of 5-2 500 mg/L. The improving five - step iodometry method could measure the sample volume was 1 - 20 ml, the relative standard deviation was0. 70%. Conclusion In the study, we find the influencing factor such as the category and dosage of reagent, blowing nitrogen pressure may affect the accuracy of chlorine dioxide＇s concentration by five - step i- odometry method. By improving, we can get more accurate results.