流动注射光度法测定水中微量氟化物的研究

在硫酸介质中，Fe^3 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Fe^3 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。

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

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.