Comparison of reflux and microwave oven digestion for the determination of arsenic and selenium in sludge reference material using flow injection hydride generation and atomic absorption spectrometry

Abstract

A microwave oven digestion procedure was developed for rapid dissolution of sludge samples (NIST SRM 2781) for the determination of As and Se. Microwave oven digestion with HNO₃ and H₂SO₄ provides results comparable to those obtained by reflux column digestion using HNO₃, H₂SO₄ and HClO₄. The experimental details for sample preparation and the flow injection hydride generation atomic absorption spectrometric method are discussed. The effects of matrix and various acid concentrations on the extraction and absorbance were also studied. The proposed method has detection limits of 0.15 and 0.17 ng ml^–1 for As and Se, respectively.