碱性过硫酸钾法总氮测定波长的探究  

Research on Different Wavelengths of Detecting Total Nitrogen Using Alkaline Potassium Per-sulfate

作　　者：李大鹏[1] 冯斌[1] 

机构地区：[1]苏州科技学院环境科学与工程学院,江苏苏州215011

出　　处：《实验室研究与探索》2016年第1期10-12,222,共4页Research and Exploration In Laboratory

基　　金：国家自然科学基金项目(51178284;51278523)

摘　　要：验证了硝酸根最大吸收峰波长能否作为总氮测定波长及不同波长对总氮测定结果的影响。结果表明,通过波长扫描0.08-2.8 mg/L硝酸根,发现最大吸收峰并非在220 nm,而出现在200-210 nm。采用碱性过硫酸钾法测定水体中的总氮含量,200-210 nm存在盐酸吸收峰干扰,但在211-220 nm波长范围内均有良好的线性关系。不同波长对加标回收率、重现性、精密度及方法检出限检验影响不大。随着测定波长的减小,标准曲线的斜率、相关系数R、摩尔吸光系数依次增加。211 nm处摩尔吸光系数达6.8×103（mol/L）-1/cm,远高于220 nm。同时,211 nm处标准曲线拟合斜率K更大。在实际地表水的测定中,以最大吸收峰（211nm）处测定总氮,与国标220 nm处测定相比较,结果并无明显差异。The maximum absorption wavelength of nitrate used for the total nitrogen wavelength and the effect of different wavelength on the concentration of total nitrogen were determined in the research. The results showed that the maximum absorption peak ranged from 200 ~ 210 nm,but it did not appear at 220 nm when the nitrate from 0. 08 to 2. 8 mg / L was scanned by the wavelength. When the concentration of total nitrogen was measured with alkaline potassium per-sulfate,a peak of hydrochloric acid was observed between 200 nm and 210 nm. However,it existed a close relationship between the maximum absorption peak and the wavelength from 211 to 220 nm. The results showed that the effect of wavelength on the detection limit of the recovery,repeatability,precision and detection limit of method could be neglected. In addition,the slope of the standard curve,the correlation coefficient and the molar absorption coefficient increased with the decrease of wavelength. The molar absorption coefficient（ ε211 nm） was up to 6. 8 × 103（ mol/L）- 1/ cm and it was higher than that at 220 nm. Moreover,the fitting slope（ K） was higher at 211 nm,too. Using maximum absorption peak wavelength（ 211 nm） of nitrate to measure the total nitrogen in the surface water had no significant difference,compared with 220 nm.

关 键 词：总氮 波长扫描 灵敏度 地表水 

分 类 号：X832[环境科学与工程—环境工程]