Application Of Fenton Reaction System In Spectrophotometric And Fluorometric Detection Of Hydrogen Peroxide

Hydrogen peroxide (H2O2) is a more ecologically friendly reagent for the disinfection and sterilization than after chemicals usually used. The concentration of H2O2 in general ranges from micromolar residual levels in foodstuff and drinking water to tens millimolar for bleaching applications and then molar for waste treatment application. A small amount of H2O2 is not harmful to human health, but it is known that H2O2 at higher concentrations creates serious problems. For example, H2O2 is extremely toxic to cells at high concentrations, and it can cause cancer in the duodenum when used at 0.1%(w/w) in the drinking. Therefore, the determination of low concentrations of H2O2 is not only of great importance in food and atmosphere; but also, in many other fields such as in biological, industrials and clinical used of H2O2. Numerous methods have been developed for the determination of H2O2. Finding an accurate and simple method with considerable rapid and low cost is an aim of all methods used for the determination of H2O2.Fenton reaction (Fe2+/H2O2) used to oxidize various compounds are one of the widely studied chemical oxidation processes. It is distinguished as one of the most powerful oxidizing agents which can be used to destroy most of organic compounds. The generated hydroxyl radical (OH) in Fenton reaction system can be used as an oxidant for the probe molecules such as methyl orange and coumarin in spectrophotometric and fluorometric method for the purpose of detection of H2O2, respectively.The responsive and rapid spectrometric method for H2O2 determination has been developed with the assistance of oxidation of methyl orange (MO) by using Fenton reactions. The absorbance spectra of oxidized MO (at the maximum absorption wavelength of 507 nm) substantially depend on the reacted of the hydroxyl radical from the decomposition of H2O2 which is of course influenced by the hydrogen peroxide concentration. The spectrophotometric method for H2O2 determination based on decolorization of MO by using a Fenton reaction is successfully developed. Under the optimal conditions, the spectrometric method for the H2O2 analysis yields a linear range of H2O2 ranging from 5.0×10-7 to 1.0×10-4 mol L-1 (R=0.997) and a detection limit (3σ/k)of 2.0×10-7mol L-1.The highly sensitive fluorometric method is proposed for the determination of H2O2 in Fenton reaction system. In this method, non-fluorescent coumarin is oxidised to highly fluorescent 7-hydroxycoumarin by hydroxyl radicals (OH) generated in a Fenton reaction which shows a maximum intensity at 456 nm and can be used as a fluorescence probe for the determination of H2O2. Under the optimal conditions, the fluorescence intensity of the reaction solution is found to be linearly proportional to the H2O2 concentration ranging from 2.0×10-8 to 2.0×10-5 mol L-1 with a detection limit of 5.0×10-9 mol L-1. The resulted linear range and low detection limit demonstrates that the established method may be an excellent method for the determination of hydrogen peroxide in foodstuffs and the residual H2O2 in milk sample satisfactorily.Finally, based on the Fenton reaction system a spectrophotometric and fluorometric method using MO and coumarin. respectively, as the substrate has efficaciously developed. After a series of possible interferences are evaluated in those methods, they are applied to detect H2O2 in the rain water and milk, respectively.