Fluorometric determination of hydrogen peroxide in milk by using a Fenton reaction system

A simple and highly sensitive fluorometric method is proposed for the determination of H2O2 in milk samples. In this method. non-fluorescent coumarin is oxidised to highly fluorescent 7-hydroxycoumarin by hydroxyl radicals ((OH)-O-center dot) generated in a Fenton reaction, and the oxidation product has strong fluorescence with a maximum intensity at 456 nm and can be used as a fluorescence probe for H2O2. Under the optimal conditions (2.5 x 10(-4) mol L-1 iron(II) ions, 4.0 x 10(-4) mot L-1 cournarin, solution pH 3.0, reaction time 9 min, and excitation at 346 nm), the proposed method presents wide linear responses between the fluorescence intensity and H2O2 concentration in a wide range from 2.0 x 10(-8) to 2.0 x 10(-5) mot L-1. with a detection limit (S/N = 3) of 5.0 x 10(-9) mot L-1. After possible interferences are evaluated for a series of chemical substances, the present method has been applied to the determination of hydrogen peroxide in milk with satisfactory results. (C) 2009 Elsevier Ltd. All rights reserved.