水中总氮测定方法存在问题的研究及改进

Research on the Problems and Improvement of Total Nitrogen Determination Method in Water

碱性过硫酸钾消解紫外分光光度法测定水中总氮采用的消解器皿是玻璃比色管,易造成空白偏高、结果偏低等问题。采用双圆柱状的消解杯对水样进行消解。结果表明,消解杯消解水中总氮,线性相关系数均大于0.999,检出限为0.05 mg/L,相对标准偏差小于5%,相对误差为0.88%~1.00%;改进后的消解器皿具有较好的精密度和准确度,能够更加准确测定水中总氮的含量。

Alkaline potassium persulfate digestion ultraviolet spectrophotometry method adopts glass colorimetric tube as digestion vessel in total nitrogen determination of water,which would cause problems like higher blank value and lower result,etc. For this purpose,the research adopted bi-cylindrical digestion cup for digesting the water sample. The result indicated that the parameters as following： the curvilinear correlation coefficients were greater than 0. 9 9 9,the detection limit was 0. 0 5 mg/L; Relative standard deviations were less than 5 % and relative error was 0. 8 8 %-1. 0 0 %. The improved digestion vessel has better precision and accuracy,which could determine the content of total nitrogen in water quality more accurately.