he deficiencies of COD detendnation by KMnO4 both in theory and in experiment were discussed. The reflux condenser being added in the course of water bath heating was suggested.

• 从理论和试验两方面论证了现行高锰酸钾法测定化学需氧量的不足，提出在水浴加热过程中增加回流冷凝装置的改进建议。