紫外二次曲线法测定硝酸盐氮方法探讨

利用紫外二次曲线法测定水体中的硝酸盐氮,测量上限可达12.00mg/L,方法检出限为0.02mg/L。分析了7个浓度的硝酸盐氮标准样,实验室内相对标准偏差为1.3%,相对误差1.3%,各淡水水样加标回收率在94%～107%之间,符合水质监测的质量保证要求。氯离子干扰分析表明:氯离子在220nm处无特定吸收,浓度高达20g/L的氯离子对测定结果也无影响。试验取3份海水样品,加标2.0mg/L,回收率为99.6%±3.2%,达到实验室质量控制要求,利用该法测定含高浓度氯离子水样中的硝酸盐氮具有一定的可行性。

Determination of Nitrate by UV Spectrophotometry of Conic

Conic equation was used in analysis of nitrate by method of UV spectrophotometry,with upper limit of 12.00mg/L and MDL of 0.02mg/L.Seven standard samples were measured with the precision of 1.3% and relative error of 1.3%.Recovery of four fresh water samples was from 94% to 107%,which satisfied with requirement of water quality monitoring.Chlorine ion showed no absorption at wave length of 220nm.Even the concentration was high as 20g/L,chlorine ion had no effect on the analysis of nitrate.The recovery of sea water samples was 99.6%±3.2%.The method is feasible to monitor NO3-N in such samples as sea water which had high concentration of chlorine ion.