Solid-phase sodium bismuthate as an oxidant in flow injection analysis: determination of manganese in effluent streams

Abstract

An alternative procedure for the flow injection spectrophotometric determination of manganese(II) using a solid-phase reactor is presented. Solid sodium bismuthate (50% m/m suspended on silica gel beads) is packed in a polyethylene column, which is then incorporated in a single-line flow system so that reagent dissolution is affected as the sample passes through the column. Mn 2+ in samples injected into a carrier stream were oxidized by solid sodium bismuthate to form MnO 4 − which were detected spectrophotometrically at 526 nm. The linear range of the system is 1–20 mg l −1 with a 3 σ detection limit of 0.38 mg l −1. The proposed system is suitable for determination of manganese(II) in effluent streams with a relative standard deviation <1.35%.