碱性过硫酸钾法测定总氮中影响因素及解决方法

Influencing Factors and Solutions of TN Determination with Alkaline Potassium Persulfate

总氮是水体中氨氮、硝酸盐氮、亚硝酸盐氮等无机氮和有机氮的总和,是反映水体所受污染程度和富营养化程度的重要指标之一。在碱性过硫酸钾-紫外分光光度法测定水中总氮时,该方法操作步骤简单,易于操作和掌握,但在实际操作中影响因素较多,其准确度难以掌握。本文通过对总氮测定中试剂的纯度、配制的方法及水浴温度、储存时间、消解的温度、压力和时间等因素的总结、探讨和分析,确定适合的测定条件,提高测定结果的准确度和精密度。

Total nitrogen（TN） is the sum of inorganic and organic nitrogen in water, such as, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen. It reflects the water pollution and eutrophication degree. The alkaline potassium persulfate UV spectrophotometric method is simple, easy to operate and control, but there are many influencing factors in actual operation and it is diffi- cult to guarantee the accuracy. The optimal testing condition are determined based analysis on purity of reagents, preparation method and water bath temperature, storage time, digestion temperature, pressure and time factors to improve the measurement accuracy and precision of the test.