SPECTROPHOTOMETRIC DETERMINATION OF HYDROGEN-PEROXIDE BY THE FORMATION OF INDAMINE DYE WITH THE CATALYST OF WATER-SOLUBLE IRONPORPHYRIN

A water-soluble iron porphyrin, a meso-tetrakis(1-methyl-4-pyridyl)porphinatoiron(III) complex (FeTMPyPX5; X=OCH3 or halide), was successfully applied as a catalyst of indamine dye formation, which can be used for the determination of hydrogen peroxide in an acidic media. The dye formation process includes an oxidative coupling of N,N-dimethylaniline and 3-methyl-2-benzothiazolinone hydrazone with hydrogen peroxide. The absorbance of the formed dye was measured at 590 nm with a spectrophotometer. The materials were stable and the reaction was specific for hydrogen peroxide without any influence of molecular oxygen at low pH, 1-2. The method showed easy handling in the concentration range of (0.3-3.7)×l0-5moldm-3 with a correlation factor: 0.9998 and RSD=1.74%. This method can be used for the determination of hydrogen peroxide generated through enzymatic processes. © 1990, The Japan Society for Analytical Chemistry. All rights reserved.