NEW SPECTROPHOTOMETRIC METHOD WITH KMnO4 FOR DETERMINATION OF HYPOCHLORITE IN COMMERCIAL BLEACHES

Abstract

Hypochlorite with a strong germicidal and bleaching action forms the active component in most commercial bleaches. The new method, an instrument-based and simple experimental procedure involves the reaction of the hypochlorite with arsenious oxide (As₂O₃) (pH 6.5) followed by the coupled reaction of residual As₂O₃ with permanganate at acidic pH. A titration procedure is described and spectrophotometric method is designed using four ranges of calibration curves to enable the determination of hypochlorite in the range 2.5 x 10^-4 to 2.4 x 10^-2 M from the KMnO₄ absorbance measurements. A series of commercial bleaches are tested using the proposed spectrophotometric method. The results proved more precise and accurate than by arsenite method.



KEY WORDS: Commercial bleaches, Hypochlorite determination, Spectrophotometric method


Bull. Chem. Soc. Ethiop. 2005, 19(1), 1-8.