Comparison of dry mineralization and microwave-oven digestion for the determination of arsenic in mussel products by platform in furnace Zeeman-effect atomic absorption spectrometry

Abstract

Two digestion procedures were compared in order to obtain an accurate method for the determination of As in mussel products using platform in furnace Zeeman-effect atomic absorption spectrometry. One procedure was based on dry mineralization of the samples and the other on microwave-oven sample digestion in closed polytetrafluoroethylene reactors. Microwave-oven digestion with HNO₃ and H₂O₂ allows the accurate determination of As in certified oyster and mussel tissue samples and provides results comparable to those found by dry mineralization of real mussel product samples, with a sensitivity of 3.9 absorbance units per µg ml^–1 and a relative standard deviation of 5% in the analysis of samples containing 8 µg g^–1 dry mass of As. Experimental conditions for the determination of As in real samples were optimized and a series of real samples analysed in order to determine the analytical characteristics of the proposed procedure. Sample treatment time was reduced from 2–3 d using dry mineralization, to 20 min per sample using microwave-oven digestion.