AbstractA spectrophotometric for the determination of hydrogen peroxide in pulp bleaching effluents is reported. The method is based on hydrogen peroxide instantly reacting with vanadium pentoxide in sulfuric acid solution, forming a peroxovanadate complex that has an absorption maximum at 454 nm. It was found that the optimum conditions were as follows: detection wavelength of 454 nm, a V2O5:H2O2 mole ratio of 2.2, and a sulfuric acid concentration of 0.5 mol/L. In order to eliminate the interference from dissolved lignin, fines, and suspended solids, the samples were acidified and centrifuged for spectroscopic quantiﬁcation. The results showed that the method has an excellent measurement precision (RSD < 0.3%) and accuracy for the quantification of hydrogen peroxide content in pulp bleaching effluents. The present method is simple and accurate, making it suitable for applications in the pulp and paper industry.