Spectrophotometric determination of hydrogen peroxide in the presence of fluoride

摘要

A simple, rapid method was required for the determination of 0.01 - 0.1M hydrogen peroxide in the presence of 10M HF and in solutions resulting from the dissolution of unirradiated nuclear fuel elements in this dissolvent. Fluoride is a serious interference in the classical spectrophotometric procedure for determining hydrogen peroxide as the yellow-colored Ti(IV)-peroxide complex. It was thought that this interference could be minimized by the addition of a fluoride-complexing metal ion. Zirconium, aluminum, and boron were studied at various metal ion to fluoride mole ratios to determine the optimum conditions for reducing the interference by fluoride when present at the 0.015M and 0.15M levels. All three were effective in reducing the interference, but only at a metal ion to fluoride ratio of one or greater. Although zirconium was the most effective complexer studied, an excess of ZR(IV) decreased the absorbance of the Ti(IV)-peroxide complex. Since excess aluminum does not interfere, a procedure was developed in which two moles of AI(III) are added for each mole of fluoride in the sample aliquot. The color develops rapidly at room temperature and is stable for at least 24 hours. The absorbance is linear over the range 1 (times) 10(sup (minus)4)M to 1.8 (times) 10-(sup (minus)3)M H(sub 2)O(sub 2) when measured in 1-cm cuvettes. The method tolerates a variety of metal ions and complexing agents at the 0.02M level.