A simple manifold flow injection analysis for determining phosphorus in presence of arsenate

Abstract

A simple manifold flow injection analysis (FIA) for determining phosphorus in presence of arsenate in water, by the on-line reduction of As(V) to As(III) using sodium sulphite. The FIA method is applicable for the determination of phosphorus in water samples containing less than 0.37μg mL⁻¹ of AsO₄³⁻ A solution obtained by mixing 6.30g of Na₂SO₃ (1M), 5.0 ml H₂SO₄ 18 M completed up to 50 ml with deionized distilled water was used to reduce on line As(V) to As(III), using a reactor of 0.30m. The limit of detection is 0.05584 ± 0.00167μg mL⁻¹ P— P0₄³⁻ and sampling frequency is 45 samples per hour. It is a simple and low cost methodology, easily applicable in the determination of phosphorus in samples of water contaminated with arsenate.