Thermal Infrared Enthalpimetry Method for the Determination of Hypochlorite in Bleaching Solutions

Thermal infrared enthalpimetry (TIE) was used for hypochlorite determination in commercial hypochlorite-based bleaching solutions. Experimental parameters were evaluated for the reaction with a hydrogen peroxide solution. The most relevant conditions were 5% H2O2 (m/m) solution, stirring speed of 250 rpm, dispensing rate of 0.57 mL s-1, and 10 s after reaction for the simultaneous temperature readings of four replicates. Agreement to reference method NBR 9425 ranging from 98.2 to 103.2% was achieved, with a low variation among measurements (relative standard deviation