Spectrophotometric determination of hydrogen peroxide in water and cream samples

A simple, rapid and sensitive spectrophotometric method is described for the determination of hydrogen peroxide using toluidine blue as a reagent. The proposed method is based on the liberation of iodine in acidic medium equivalent to the amount of hydrogen peroxide present. The liberated iodine bleaches the blue color of toluidine blue and is measured at 628 nm. The decrease in absorbance is directly proportional to hydrogen peroxide concentration and obeys Beer's law in the range 0.2 x 10(-6)-14 x 10(-6) mol L-1. The molar absorptivity, sandel's sensitivity, detection limit and quantitation limit of the method were found to be 1.82 x 10(4) L mol(-1) cm(-1), 2.01 x 10(-9) mol L-1, 1.41 x 10(-6) mol L-1 and 4.28 x 10(-6) mol L-1 respectively. The results of analysis of the proposed method are compared favorably with those from a reference method.