水质中总氮测定的影响因素分析

采用碱性过硫酸钾消解―紫外分光光度法对水质中总氮含量进行测定,分析影响总氮测定结果的各种因素。实验结果显示,测定水中总氮过程中,实验所用纯净水、过硫酸钾纯度及碱性溶液存放时间对空白吸光度有明显影响,消解时间和冷却放置时间也会影响测定的空白吸光度和相对误差。在实验确定的最佳条件下对样品进行测定,结果准确可靠。

Study on the Influencing Factors of Total Nitrogen Determination in Water Quality Analysis

In this paper, total nitrogen in water was determined by alkaline potassium persulfate digestion-ultraviolet spectrophotometric method. The influencing factors were discussed in detail. It was shown that the blank absorbance in the determination of total nitrogen is obviously influenced by the purity of reagent and the conserving time of alkaline potassium persulfate. Furthermore, the digestion time and the cooling time after digestion also affect the blank absorbance and relative error. Under the optimum conditions, the determining result was accurate and reliable.