比色管密封性对水质总氮测定的影响

Effect of Colorimetric Tube Tightness on Total Nitrogen Determination in Water Quality Analysis

在利用《GB11894-89水质总氮的测定碱性过硫酸钾消解紫外分光光度法》测定水质总氮过程中,经常出现空白值偏高、样品结果值与实际值偏差较大等情况。为了提高总氮测定结果的准确度,研究了比色管密封性对水质总氮测定的影响。结果表明,比色管的密封性对空白值和样品测定结果都确实产生了影响,建议总氮实验过程中选用高密封性比色管。

The standard method for determination of the total nitrogen in water was the alkaline potassium persulfate digestion UV spectrophotometric method（ GB11894-89）. However,high blank value and the deviation between the sample value and the actual value are always occurred using this method. In order to improve the accuracy of the total nitrogen determination results,this paper studied the influence of the tightness of the colorimetric tube. The results indicated that the tightness of the cuvette actually had impacts on the blank value and the determination results. It was recommended that the high-tight colorimetric tube should be selected in the experiment of total nitrogen determination.