微顺序注射-镉柱还原分光光度法测定海水中总氮

Determination of Total Nitrogen in Seawater by Micro Sequential Injection-Cadmium Column Reduction Spectrophotometry

基于微顺序注射-阀上实验室,采用镉柱还原-偶氮染料染色分光光度法测定海水中总氮,对实验参数进行了优化,并进行了干扰因素实验。结果表明,海水中主要离子和盐度对本实验方法测定会产生干扰,采用一定盐度的国家标准海水作为溶剂制备系列标准溶液,可消除干扰。海水中总氮浓度在0.03~1.00 mg/L范围内与吸光度呈良好线性,线性相关系数r=0.9993;测定含氮浓度为0.2 mg/L的国家标准海水,相对标准偏差（RSD）为4.9%;方法的检出限为0.010 mg/L;样品加标回收率在99.5%~101.1%之间。经t检验分析,本方法与国标方法测定数据无显著性差异,可用于海水样品中总氮的测定。

A cadmium column reduction-azo dyes spectrophotometric method based on micro sequential injection lab-on-valve was established for the determination of total nitrogen in seawater. The experimental parameters were optimized,and the interference experiment was carried out. The results showed that the interference of the main components and salinity in sea water could be eliminated by using a series of standard solution prepared by national standard seawater with certain salinity. The concentration of total nitrogen in seawater was linear with the absorbance in the range of 0. 03- 1. 00 mg / L with a correlation coefficient of0.9993. When determining the national standard seawater at nitrogen concentration of 0.20 mg / L,the relative standard deviation（ RSD） was 4.9%,the detection limit was 0.010 mg / L,and the recoveries were 99.5%-101.1%. There were not significance differences between the results of this method and national standard method in the t-test analysis. The method is suitable for the determination of total nitrogen in seawater.