离子色谱法测定地表水中总氮

采用碱性过硫酸钾消解水样，OnGuardⅡBa柱萃取、过滤，去除消解液中大量硫酸盐，离子色谱法测定地表水中总氮含量。试验表明，方法在0ms／L～20．0mg／L之间线性良好，相关系数r为0．9994，方法检出限为0．007mg／L。该方法与国标法同时测定标准物质，测定值均在定值范围内，6次平行测定结果的RSD分别为2．3％和1．8％，地表水样的加标回收率为95．7％～105％。实际水样的测定结果与国标法比对，无明显差异。

Determination of Total Nitrogen in Surface Water by Ion Chromatography

The total nitrogen content in surface water was determined by ion chromatography after alkaline potassium persulfate digestion followed by OnGuard I1 Ba column to eliminate a mass of sulfate. Tests showed that the good linearity was obtained between 0 mg/L - 20.0 mg/L, with the correlation coefficient was 0. 999 4. The method detection limit come to be 0. 007 mg/L. Simultaneous determination of standard substance using the current method and the national standard method, the determined values were both in the range of customized. The RSDs of 6 parallel determination were 2.3% and 1.8% , and the spiked recovery of surface water sample ranged from 95.7% - 105%. There were no significant difference between the current method and the national standard method for determining real samples.