硫氰根对COD与TOC测定的影响及修正方法

Influence of thiocyanate on the determination of COD and TOC and its correction method

考察了不同浓度梯度的SCN-溶液对COD与TOC测定值的影响,结果表明:SCN-浓度和COD、TOC测定值之间呈现显著的线性关系,1 mg SCN-对COD、TOC的贡献值分别为1.065 5、0.202 1 mg,与理论计算值1.103 4、0.206 9 mg接近。加标回收率实验确定该线性方程可靠,COD、TOC的加标回收率分别为95.9%~104.5%、95.1%~104.3%。χ~2检验结果证明,线性方程计算值与理论值之间的偏离程度不大。利用该线性方程可较好地修正实际水样中有机污染物引起的COD与TOC情况。

The influences of thiocyanate（SCN-） solution with different concentrations and gradients on the measured values of COD and TOC have been investigated. The results show that SCN^- concentration has remarkable linear relationship with the measured values of COD and TOC. The contribution values of 1 mg SCN^- to COD is 1.065 5 mg and to TOC is 0.202 1 rag. The data are close to the theoretical calculation values of COD as 1.103 4 mg and TOC as 0.206 9 rag. It is ascertained by the standard recovery rates that the linear equation is reliable, and the recovery rates of COD and TOC are in the ranges of 95.9%-104.5% and 95.1%-104.3%, respectively. The X2 test result proves that the deviation degree between the linear equation calculation value and theoretical calculation value is small. The linear equation could be used for correcting the situation of COD and TOC caused by organic pollutants in actual water samples quite well.