流动注射褪色光度法测定水样中的亚硝酸盐

Determination of Nitrite in Water by Flow Injection Decolorizing Spectrophotometry

在酸性环境中,双氧水和偏钒酸铵反应可生成有色的过氧钒酸盐,而亚硝酸盐可使有色的过氧钒酸盐褪色,褪色产物的检测波长为470 nm,据此建立了流动注射褪色光度法测定亚硝酸盐的新方法。该方法简单、快速、选择性好。现对影响该方法的显色体系和流路体系进行了优化。在优化的实验条件下,当亚硝酸盐(NO_(2)^(-)-N)浓度在50~2500μg/L时,浓度与峰高呈良好的线性;检出限为4.5μg/L;重复测量结果之间的相对标准偏差为0.64%(1000μg/L亚硝酸盐,n=13)。利用本法分析不同水样中的亚硝酸盐,回收率在97.9%~101.1%之间,测定结果与国标法一致。

In acidic environment,the reaction of hydrogen peroxide and ammonium metadadate can produce colored peroxovanadates,and nitrite can make the colored peroxovanadates fade.The detection wavelength of the fading products is 470 nm.Based on this,a new method for the determination of nitrite by flow injection fading spectrophotometry was established.This method is simple,fast and selective.The color rendering system and flow path system which affect the method are optimized.Under the optimal conditions,the calibration graph for nitrite was linear over the concentration range is 50.0~2500.0μg/L.The detection limit was 4.5μg/L;the relative standard deviation was 0.64%for a solution containing 1000μg/L nitrite(n=13).The recovery of nitrite from three samples ranged from 97.9%~101.1%of the added amount.The results obtained for nitrite by the proposed method were in very close agreement with those using the offi cial method.