高氯低COD值水样的无汞快速测定法

摘要

AgNO3 and CrK(SO4)2·12H2O was used instead of HgSO4 for elimination of chloride ion inter-ference in the determination of COD.Meanwhile,the concentration of potassium dichromate was reduced to 0.100 mol/L.A mixture of sulphuric acid and phosphor acid was used instead of sulfuric acid.The determina-tion of standard samples and examination of actual samples showed that this method had a good accuracy and pre-cision for determination of low-COD water samples containing chloride ion below 25 000 mg/L,and the silver re-cycling could also be achieved.%以硝酸银和硫酸铬钾代替硫酸汞来消除 COD 测定中的氯离子干扰，同时将重铬酸钾溶液的浓度降低为0．100 mol／L，并用硫磷混酸代替硫酸，该方法经过对标准样品和实际样品的测定，表现出对于测定氯离子含量低于25000 mg／L的高氯低 COD 值水样具有较好的准确度和精密度，同时可以实现银盐的回收再利用。