化学需氧量测定方法对比分析

Comparative analysis of chemical oxygen demand determination methods

通过《水质化学需氧量的测定重铬酸盐法》(HJ828-2017)手工法、《水质化学需氧量的测定重铬酸盐法》(HJ828-2017)仪器法、《水质化学需氧量的测定分光光度法》(DB31/199-2018附录B)、《化学需氧量(CODCr)水质在线自动监测仪技术要求及检测方法》(HJ377-2019)四种方法对高浓度和低浓度水样进行测定对比,并在氯离子浓度不同的情况下,对比四种方法抗氯离子干扰的结果。实验结果表明:①四种分析方法测定结果基本一致,检出限、精密度、准确度、加标回收率均符合质量控制要求。②测定高浓度样品时,四种方法都比较稳定准确,测定低浓度样品时,重铬酸盐手工法偏差较小。③重铬酸盐手工法和重铬酸盐仪器法可测定氯离子含量小于1000mg/L的水样,分光光度法和在线自动监测法可测定氯离子含量小于2 000mg/L的水样。

The high concentration and low concentration water samples were determined and compared by four methods:water quality-determination of the chemical oxygen demand-Dichromate method(HJ 828-2017)manual method,water quality-determination of the chemical oxygen demand-Dichromate method(HJ 828-2017)instrumental method,water quality-determination of chemical oxygen demand-Spectrophotometer(DB31/199-2018 appendix B),technical specifications and test procedures for water quality on-line automatic monitoring equipment of chemical oxygen demand(CODCr)(HJ 377-2019).And the results of four methods were compared under different chloride ion concentrations.The results show that:①The results of the four analytical methods were basically the same and the detection limit,precision,accuracy and recovery rate met the requirements of quality control.②In the determination of high concentration samples,the four methods are stable and accurate.In the determination of low concentration samples,the deviation of dichromate manual method is small.③Dichromate manual method and dichromate instrumental method can be used to determine water samples with chloride ion content less than 1000 mg/L.Spectrophotometer and on-line automatic monitoring method can be determined for water samples with chloride ion content less than 2000 mg/L.