改进重铬酸钾法快速测定水样CODcr

Rapid determination of COD in water sample by using potassium dichromate

研究了用硫酸锰代替贵金属硫酸银作催化剂,在H2SO4—H3PO4介质中,重铬酸钾回流法测定水样中CODcr的新方法。通过实验,确定了最佳测定条件:MnSO4浓度为1×10-1mol.L-1;混酸溶液(H2SO4:H3PO4)=5:1(体积比);回流时间10min。并与标准方法进行了对比,准确度和精密度同标准法相近,大大节约了分析时间。

A newanalytical method of the chemical oxygen demand （COD） for water sample is developed. The manganese sulfate substitutes the silver sulfate for the catalyst with the H2SO4-H3PO4 instead of H2SO4. The results show that the optimal condition is the 1×10^-1 mol. L^-1 of manganese sulfate with the ratio of H2SO4 to H3PO4 = 5：1 and 10-minutes of the condensation time. It is compared with the standard model and the analytical time is greatly reduced with almost the same accuracy and precision.