流动注射光度法测定水中微量氟化物的研究

Study on determination of trace fluoride in water by flow injection-spectrophotometry

在硫酸介质中,Fe3+对H2O2氧化甲基橙退色反应具有强烈的催化作用,而游离的F-与Fe3+形成稳定的配合物可阻抑催化作用,阻抑程度与F-量呈线性关系。基于此,与流动注射技术相结合,建立了测定水中微量氟化物的流动注射催化光度分析法。方法测定F-的检出限为0.08mg/L,测定的线性范围为0.02～4.0mg/L,测定频率为50次/h。方法灵敏度高,选择性较好,分析速度快,可用于测定自来水中痕量氟化物。

In sulfuric acid medium, trace Fe3+ catalyzes strongly the fading reaction of methyl orange when oxidized with H2O2 , free F- forms a stable complex with Fe3+ , thus reducing the catalytic effect of Fe3+ , its reducing extent is linear with the concentration of F-. Based on this reaction, a rapid and simple flow injection-spectrophotometric method for determination of trace fluoride in water has been established. It is shown that the detection limit and linear range were 0.08 mg/L and 0. 02-4.0mg/L respectively. The determination frequency was 50 times/h. The method has high sensitivity, better selectivity and fast analytical speed. It can be applied to the determination of trace fluoride in tap water.