DPD分光光度法测定过硫酸氢钾复合粉中有效氯含量

Determination of available chlorine by DPD method in the compound peroxymonosulphate powder

关键词:  过硫酸氢钾  DPD光度法  有效氯

Key words:  Potassium monopersulfate  N,N'-diethyl-p-phenylenediamine method  available chlorine

摘要:

建立了测定过硫酸氢钾复合粉中有效氯含量的N,N'-二乙基-1，4-苯二胺（DPD）分光光度法。以碘酸钾标准溶液为对照，将DPD溶液和磷酸盐缓冲液（pH 6.5）混合后，加入待测样品，在325 nm处对三者反应形成的红色半醌式化合物进行分光光度测定。结果表明：有效氯浓度在0.05～2.0 mg/L范围内与吸光度值呈现良好的线性关系，相关系数r为0.9992；方法重复性好（RSD≤2.65%，n=6）；准确度高，平均回收率为93.68%～105.55%（RSD≤1.29%，n=6），且与碘量滴定法测定的结果相比在统计学上无显著差异。该法简单、准确、重现性好，可作为过硫酸氢钾复合粉有效氯含量的测定方法。

Abstract:

Abstract: A N,N'-diethyl-p-phenylenediamine (DPD) method was established for the determination of available chlorine in the compound peroxymonosulphate powder. The sample was added into the mixture of DPD solution and phosphate buffer solution, then the red half-quinonoid compound formed by the reaction was spectrophotometrically determinated at λ = 325 nm. The results showed that the calibration curves were good linear between the absorbance and the concentrations of 0.05～2.0 mg/L with the correlation coefficient r=0.9992, the repeatability was good with RSD≤2.65%, the average recovery with blank samples was 93.68%～105.55% with RSD≤1.29%, which ensures its adequate accuracy, and there was no significant differences in content of available chlorine between the DPD method and the iodimetric titration. The DPD method is simple and accurate. It could be adopted for the quality control of the contents of available chlorine in the compound peroxymonosulphate powder.