In situ preconcentration and determination of trace arsenic in botanical samples by hydride generation-graphite furnace atomic absorption spectrometry with Pd-Zr as chemical modifier

A method has been described for the determination of arsenic by graphite furnace atomic absorption spectrometry (GFAAS) with hydride generation (HG) and in situ preconcentration techniques using Pd-Zr chemical modifier. The experimental conditions studied include acidity, concentration of NaBH4, adsorption temperature, amounts of modifier, which affect the generation of hydride, adsorption efficiency and the pyrolysis and atomization temperatures. The highest pyrolysis temperature and adsorption efficiency of arsine were obtained when Pd-Zr mixture was used as the adsorption agent and chemical modifier. The characteristic mass of the method (gives an integrated absorbance of 0.0044 s) was found to be 18 pg and the absolute detection limit (3sigma) of 15 pg was obtained. The proposed method was applied to the determination of arsenic in botanical samples with a recovery range of 96-105%. (C) 2003 Elsevier B.V. All rights reserved.