The determination of NH4+-N in water by indophenol blue is sensitive and highly specific.However the long color reaction time leads to the low efficiency and restricts its application.In this paper,the determination of NH4+-N in water by indophenol blue was studied,including the effects of temperature,catalysts of Mn2+ and acetone on the reaction.The results of the research show that,the rate of reaction accelerates with the temperature increasing,and the balance of reaction is reached in 15 min at 40 ℃.Catalyst Mn2+ also can accelerate the rate of reaction significantly,the most appropriate dose of Mn2+ being 50 mg/L.However,the effect of acetone in the reaction is proved to be invalid.The precision and accuracy of NH4+-N determination proposed in this paper meet the requirements in practice.%改进了靛酚蓝分光光度法测水中氨氮的方法,研究了不同温度、催化剂锰和丙酮对靛酚蓝反应的影响.结果表明,提高反应温度可以有效加快反应速度,恒温水浴40℃条件下,显色反应可以在15 min内达到反应平衡.加入催化剂Mn2+可以有效加快反应速度,50 mg/L为最佳浓度,浓度过高和过低都不利于反应的顺利进行;而催化剂丙酮对反应没有促进作用,反而有抑制作用.测定结果的精密度和准确度均能满足水中氨氮含量的分析要求.
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