Catalytic kinetic spectrophotometric determination of trace iron with light green SF and hydrogen peroxide

A new catalytic kinetic method for the determination of trace iron was established based on the catalytic action of Fe(Ⅲ)on the oxidative fading reaction between light green SF and hydrogen peroxide in sulfuric acid medium.The calibration curve was linear in the range of 0.012-0.112 μg/mL for Fe(Ⅲ),and the linear regression equation was ΔA=0.150 2+6.214ρ(μg/mL)with the correlation coefficient of 0.999 0.The detection limit was 9.65×10-9 g/mL for Fe(Ⅲ).The method has been applied to determine trace Fe(Ⅲ)in coal and water samples with the relative standard deviations of 2.6%-5.5% and recoveries of 90%-107%.