Flow injection voltammetric determination of hypochlorite and hypobromite as bromine by injection into an acidic bromide eluent and the indirect determination of ammonia and hydrazine by reaction with an excess of hypobromite

Abstract

Hypochlorite, in solutions with a wide range of pH, can be determined as bromide by flow injection voltammetry at a glassy carbon electrode by injection into a dilute sulphuric acid eluent containing 1%m/V of potassium bromide. With 2.5 M sulphuric acid eluent the rectilinear range is from 0.08 to 2 × 10^–3M. Hypobromite solutions containing an excess of bromide can be analysed similarly, omitting potassium bromide from the eluent.

Ammonia and hydrazine in the range 0.05–0.7 × 10^–3M were determined with a relative error of <5% by reaction with 1 × 10^–3M hypobromite in phosphate buffer solution (pH 9.8) and determining the excess of hypobromite by flow injection voltammetry.