Simultaneous determination of hydride forming elements (As, Bi, Ge, Sb, Se) and Hg in biological and environmental reference materials by electrothermal vaporization–microwave induced plasma-optical emission spectrometry with their in situ trapping in a graphite furnace

Abstract

The approach for the simultaneous determination of five hydride forming elements (As, Bi, Ge, Sb, Se) and Hg by microwave induced plasma optical emission spectrometry (MIP-OES) is described. The combination of hydride generation (HG) and in situ preconcentration of the analytes onto the Pd (for As, Bi, Ge, Sb, Se) or Au (for Hg) pretreated interior wall surfaces of a graphite furnace (GF) has been used as a collection technique. The furnace comprised the electrothermal vaporization (ETV) sample introduction unit of a MIP-OES detection system. Compromise conditions are established. The trapping temperature was 300 °C and the vaporization temperature 2100 °C. Calibration was achieved via the method of standard additions. Absolute limits of detection (3σ_blank criterion, peak height) were 3, 8, 15, 8, 20 and 10 ng for As, Bi, Ge, Hg, Sb and Se, respectively. System efficiency for the generation and sequestration of the hydrides averaged better than 55%. The HG-ETV-MIP-OES method was successfully applied to the determination of As, Bi, Ge, Hg, Sb and Se in several certified biological and environmental reference materials (hair, tissue, leaves, soil, sediment, fly ash) with a precision of 8–15% RSD at a concentration 50-fold above the LOD, following high pressure decomposition and dissolution of the samples by microwave heating in a mixture of acids. The results obtained by this method were in fair agreement with the reference value.