Analytical Sciences

Kinetic Flow-injection Determination of Hydrogen Peroxide by Use of Iron(III)-catalyzed Coloration and Its Application to the Determination of Biological Substances

Norie MAEUCHIHARA,* Shigenori NAKANO,** and Takuji KAWASHIMA* 

*Laboratory of Analytical Chemistry, Department of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
**Department of Environmental Sciences, Faculty of Education and Regional Sciences, Tottori University, Tottori 680-0945, Japan

A kinetic flow-injection (FI) method is described for the determination of hydrogen peroxide. This method is based on an iron(III)-catalyzed oxidative coupling of 4-aminoantipyrine with N,N-dimethylaniline by hydrogen peroxide. By measuring the change in the absorbance of the dye formed at 560 nm, 1x10^-6 - 6x10^-4 M hydrogen peroxide could be determined with a sampling rate of 15 h^-1. The relative standard deviation (n = 30) was 0.8% for 5x10^-5 M hydrogen peroxide. There was little interference of the co-existing ions and compounds. After introducing some immobilized enzyme reactors to the FI system, the proposed method allowed the determination of glucose and uric acid ranging from 1x10^-6 to 6x10^-4 M with relative standard deviations of below 2%. The applicability of the method was demonstrated by determining these substances in serum samples.

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