烘箱消解-镉铜还原法测定地表水中总氮

Determination of Total Nitrogen in Surface Water by Oven Digestion-Cadmium Copper Reduction Method

提出了烘箱消解-镉铜还原法测定地表水中总氮含量的方法。氮的浓度在7.637×10-4～1.375×10-2 mmol.L-1范围内与其吸光度呈线性关系,检出限(3S/N)为6.704×10-5 mmol.L-1。对人工海水、实验室自来水、海水和湖水中总氮进行测定,其回收率和相对标准偏差(n=6)分别在96.7%～101.3%和3.7%～3.9%之间。

A method for the determination of total nitrogen in surface water by cadmium-coper reduction method with sample digestion in oven was proposed. Linear relationship between values of absorhance and concentration of nitrogen was obtained in the range of 7. 637×10^-4--1. 375×10^-2mmol·L-1, with detection limit （3S/N） of 6. 704×10^-5 mmol·L^-1. The proposed method was applied to the determination of total nitrogen in samples of artificial sea water, running water, sea water and lake water; test for recovery was made by standard addition method, giving values of recovery and RSD＇s （n=6） in the ranges of 96.7%--101.3% and 3.7%--3.9% respectively.