原子吸收法测定环境水样中化学需氧量

Determination of Chemical Oxygen Demand in Aqueous samples by AAS

在Ｈ２ＳＯ４介质中用Ｋ２Ｃｒ２Ｏ７同ＣＯＤ水样反应，反应后水相中过量的Ｃｒ（Ⅵ）以Ｃｒ２Ｏ２－７形式被ＴＯＡ萃入有机相中，而生成的Ｃｒ（Ⅲ）则留在水相，用ＡＡＳ测定有机相中的Ｃｒ（Ⅵ）或水相中的Ｃｒ（Ⅲ）都可求得ＣＯＤ含量。本法简便快速、需样量少、且测定结果同标准方法（ＣＯＤＣｒ法）一致，回收率为９８％～１０８％，平均标准偏差为３．３％。

his paper investigated an indirect AAS method for determining chemical oxygen demand in aqueous samples.K2Cr2O7 reagent was added to the sample solution to react with organic substances in H2SO4 medium,after reaction Cr2O2-7 in the solution was extracted into organic phase of TOA,and the Cr() produced remained in the solution,Cr() in teh organic phase or Cr() in the aqueous solution was determinaed by AAS.The contents of COD in samples could be obtained.This method is simple,fast,and of microscale ,the results agreed well with those obtained by volumetric method.The recoveries are between 98%108% and the average relative standard deviation is 3. 3%.