环境水样CODcr测定方法中催化剂的改进研究

用MnSO4作催化剂高温消解法测定环境水样CODcr,探讨了催化剂选择及用量、混酸的用量、氯离子对测定结果影响,结果表明：选择50 g·L-1 MnSO4溶液0.20 mL,硫酸/磷酸（5∶1）混酸3.00 mL进行测定,其结果与国标法无显著性差异（P=0.05）,当C1浓度低于500 mg·L-1对测定结果无干扰,无需添加有毒的硫酸汞作掩蔽剂,避免了对环境的二次污染,样品测定结果相对标准偏差RSD≤3.8％（n=5）,加标回收率为96.1％～101.1％.该方法具有操作简单、快速、准确等优点,适用于大批量环境水样COD的测定.

Improvement Study on Catalyst for CODcr Determination of Environmental Water Samples

One of the high temperature digestion methods for determining the environmental water C ODcr used MnSO4 as a catalyst. In this paper, we discus the effect of the choice and dosage of catalyst and the amount of mixed acid and chloride ions on the determination results, and the results show that the result of the determing method, which selected 0. 2 mL 50 g · L-1 manganese sulfate solution and 3.00 mL mixed acid （the ratio of Sulfuric acid and Phosphate is 5： 1）, had no significant difference with the GB method. It was without interference when the concentration of Cl- less than 500 mg · L-1 in the detection of samples, and the RSD was 43.8%（n=5）, and the recovery rate was 96.1%-101.1%. This method is sample, fast, accurate and applicable to the analysis of large numbers of samples.