基于环境监测实践的COD分析试剂浓度的优化

Optimization of Analytical Reagent Concentration of COD Based on Environmental Monitoring Practice

为避免现行COD测定国标方法中分段测定的繁琐,将重铬酸钾和硫酸亚铁铵的浓度分别降至0.100mol/L和0.02mol/L,并进行了一系列实验研究。结果表明,改进后的方法省去了对样品浓度预判的环节,能够用一套分析试剂对浓度在13mg/L～300mg/L范围内的样品进行准确定量,相对误差为-2.71%～0.33%,相对标准偏差为0.38%～3.85%,回收率为96.5%～104%,既保证了测定结果的准确性、精密性,又使测定过程更加简便,对环境监测实践具有重要的积极意义。

To get rid of the trouble of piecewise determination defined in national standard determining method of COD,the concentration of potassium dichromate and ferrous ammonium sulfate was reduced to 0.100 mol/L and 0.02 mol/L.A series of experiments were followed.The result showed the improved method could precisely quantify those samples ranging from 13 mg/L to 300 mg/L by only a set of analytical reagent without predicating their concentration.The determination data showed the method had good accuracy,precision and high recovery,with relative error from-2.71%to 0.33%,relative standard deviation from 0.38%to 3.85%,recovery from 96.5%to 104%.Compared to national standard determining method of COD,the determination process of the improved method was simpler,and it was of great and active significance to environmental monitoring practice.