Catalytic Kinetic Spctrophotometric Determination of Trace Iron (III) with 2-(5-Carboxy-1,3,4-triazolylazo)-5-diethylamino Aniline and Hydrogen Peroxide

A new catalytic kinetic method for the determination of trace iron(Ⅲ)is established based on the catalytic action of Fe3+ on the oxidative fading reaction between 2-(5-carboxy-1,3,4-triazolylazo)-5-diethylamino aniline(CTZAN)and hydrogen peroxide in the medium of HAc-NaAc at pH 3.5 and heating conditions.The maximum of the absorbance shows at 425 nm.The calibration curve was linear in the range of(0.01—0.20)mg/L for iron,and the linear regression equation is ΔA= 4.491ρ+ 0.006 6(ρ:mg/L)with the correlation coefficient of 0.998 2.The detection limit is 2.02×10-9 g/mL for iron.The method has been applied to determine trace iron in flour and hair samples.The results are good agreement with the values obtained by atomic absorption spectrometry.