Determination of Hydrogen Peroxide in Bleaching Agent

An appropriate analytical procedure was offered for correct determination of hydrogen peroxide in commercially available bleaching agents normally containing nonionic surfactants. Nonionic surfactant retarded markedly the catalysis for hydrogen peroxide decomposition probably due to complex formation from molybdenum atoms in catalyst, e.g. ammonium molybdate, and polyoxyethylene groups of surfactant. This retardation effect of surfactant caused incorrect estimation of hydrogen peroxide concentration in bleaching agent. Correct determination became possible when bleaching agent was diluted to less than 1.0% in order to minimize the retardation effect of nonionic surfactant on hydrogen peroxide Currently available bleaching agents for domestic use mostly contain anionic or nonionic surfactants intending to make bleaching more effective. Nonionic surfactants are used in hydrogen peroxide bleaching agents for the treatment of protein fi bers (wool and silk), and anionic surfactants in hypochlorite bleaching agents for cellulose fi bers (cotton and hemp). The determination of hydrogen peroxide or hypochlorite is necessary to estimate oxidizing ability of bleaching agents. Iodometry 1) is generally applicable to determine these oxidants. In the determination of hydrogen peroxide in bleaching agent by means of iodometry, ammonium molybdate is often added as catalyst to accelerate the decomposition of hydrogen peroxide. Recently the author noted that nonionic surfactant retarded markedly the catalysis of molybdate possibly by complex formation, resulting in incorrect estimation of oxidizing ability of the bleaching agents containing hydrogen peroxide. The present paper aims to offer an appropriate analytical procedure for the determination of hydrogen peroxide in the presence of nonionic surfactant through detailed examination of the poisoning effects of the surfactant on hydrogen peroxide decomposition catalysts.