spectrophotometric method for hydrogen peroxide determination through oxidation of organic dyes

hydrogen peroxide is an important mild oxidant which is widely used in various applications including remediation of waste waters and drinking water resources. the safe level of h2o2 residue has to be controlled through accurate and precise measurement methods. a facile spectrophotometric method for the determination of hydrogen peroxide is based on the reaction of iodine solution with toluidine blue (tb). to increase the applicability, accuracy and sensitivity of the method, direct reactions of hydrogen peroxide and iodine solution with tb, methylene blue (meb), methyl blue (mb) and a diazo derivative of 1,3-diamino benzene (mada) were studied. based on the results of this study, the method was modified using mb instead of tb. the reasons concerned single peak visible spectrum, higher extinction coefficient, linear spectrophotometric responses at three different wavelengths during its oxidation by iodine and stability at low ph(s) and higher temperatures.