Catalytic kinetic spectrophotometric determination of trace iron (III) with 2-(5-carboxy-1,3,4-triazolylazo)-5-diethylaminobenzoic acid and hydrogen peroxide

In this paper,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-carboxyl-1,3,4-triazolylazo)-5-diethylaminobenzoic acid (CTZDBA) and hydrogen peroxide in the medium of HAc-NaAc at pH 4.0 and heating conditions.The maximum of the absorbance shows at 581 nm.The calibration curve is linear in the range of 0.0008～0.04 mg/L for iron,and the linear regression equation is A=25.325ρ-8.02×10-3 (ρ:μg/mL) with the correlation coefficient of 0.9977.The detection limit is 3.78×10-10 μg/mL for iron.The method has been applied to the determination of trace iron in flour and hair samples.The results are good agreement with the values obtained by atomic absorption spectrometry.