分光光度法测定总氮的准确度研究

采用碱性过硫酸钾消解紫外分光光度法测定水中总氮时常出现空白值偏高、样品平行性较差、实验准确度不高等现象.为此,从总氮的测定过程出发,探讨了影响总氮测定的主要因素,有利于提高水质总氮测定的准确度.结果表明,分析试剂纯度、实验用水水质、器皿的清洗程度等对总氮的测定均有一定影响,适当延长消解时间与提高消解温度也有利于降低总氮的空白值.因此可通过优化各实验条件来提高实验的准确性,以保证实验室的设备仪器、检测人员和环境等条件满足分析要求.

Discussion on Accuracy of Measuring Total Nitrogen by Spectrophotometric Method

The alkaline potassium persulfate digestion UV spectrophotometric method for determining total nitrogen in water has notable disadvantages of high blank value, poor parallelism and low accuracy.The main effected factors of determination the total nitrogen was discussed according to the measure process, which was helpful to improve the accuracy of determining the total nitrogen in water.The results showed that reagent purity, experiment water quality and digestion conditions had a certain effect on the determination of total nitrogen.In addition, prolonging the digestion time and increasing the digestion temperature would helpful to reduce the blank value of total nitrogen.Therefore, it is feasible to improve the accuracy of the experiment by optimizing the experimental conditions to ensure the laboratory equipment, testing personnel and environmental conditions meet the analysis requirements.