The COD of water sampling may have different results varying from kinds and concentrations of oxidizing agent, acidity of reaction solution, reaction temperature and time and if there are catalysts.

• 摘要水样的化学需氧量，可由于加入氧化剂的种类及浓度，反应溶液的酸度，反应温度和时间，以及催化剂的有无而获得不同的结果。