关于过硫酸钾氧化-紫外分光光度法测定水中总氮方法改进探讨  

Discussion on the Improvement of Determination of Total-Nitrogen in Water by Potassium Persulfate Oxidation-UV Spectrophotometry

作　　者：郑京平 

机构地区：[1]福建省测试技术研究所,福州市北环中路61号350003

出　　处：《光谱实验室》2011年第1期210-217,共8页Chinese Journal of Spectroscopy Laboratory

摘　　要：针对海水中总氮的测定较繁琐,中间过程长,干扰物质多,分析时间长,重现性差,提出了采用硼酸-氢氧化钠缓冲体系,通过控制溶液酸碱度,消除海水中钙、镁离子对测定的干扰,实现用碱性过硫酸钾氧化-紫外分光光度法直接测定海水中总氮含量。对于成分复杂,色度较高且铵氮含量较高的地表水,采取延长消解时间,降低溶液酸碱性来抑制氨氮挥发所造成损失。采用改进后的方法测定水中总氮,总氮质量浓度在0.01—8.00mg/L范围内符合比耳定律,其相关系数为0.9999,加标回收率为94.5%—102.5%,RSD<2%,实验表明该方法操作简单,稳定性强,且灵敏度,准确度、精密度均令人满意。The determination of total nitrogen in the seawater is a little difficult due to the long time course of analysis,and there are also many influences.Based on the boric acid-sodium hydroxide buffer system,by controlling the pH of the solution,the interference of Ca2＋ and Mg2＋ can be eliminated in method for the determination of the nitrogen in the seawater directly by Alkaline persulfate oxidation-UV spectrophotometry.Extending digestion time and reducing the alkaline were used to control the evaporation of ammonium.With the improving method,the concentration of total nitrogen is detected in the range of 0.01—8.00mg/L,which follows the Beer law with the correlation coefficient of 0.9999 and the recovery of standard addition is 94.5% to 102.5%,RSD2%.The method is easy,stable,sensitive,accuracy and satisfied.

关 键 词：总氮 海水 钙离子 镁离子 消解时间 硼酸 

分 类 号：O657.32[理学—分析化学]