Analusis 28, 830-834 (2000)
DOI: 10.1051/analusis:2000151

Development of a microwave sample preparation method for the determination of arsenic in humus and moss samples by graphite furnace atomic absorption spectrometry

P. Perämäki¹, M. Pesonen¹ and J. Piispanen<sup>2

1</sup>  University of Oulu, Department of Chemistry, PO. Box 3000, FIN-90014 University of Oulu, Finland
²  Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland

(Received July 11, 2000; revised November 28, 2000; accepted December 5, 2000.)

Abstract
Two sample decomposition methods were optimized for the determination of arsenic by graphite furnace atomic absorption spectrometry (GFAAS) in moss and humus samples. In the first method, 5,0 ml of HNO₃ and 3,0 ml of H₂O₂ were used for the decomposition of 500 mg of sample. When humus samples were decomposed in this way a slight, undissolved residue remained. Therefore, another sample decomposition method, including hydrofluoric acid, was also tested (5,0 ml HNO₃; 3,0 ml H₂O₂; 0,4 ml HF; 2,5 ml H₃BO₃). Pyrolytically coated graphite tubes, equipped with integrated or L'vov platfoms, were used in the determination of arsenic by GFAAS. Palladium-magnesium nitrate was used as a matrix modifier. Several reference materials (e.g. humus, moss, lichen, sea lettuce) were analyzed.

Key words: Arsenic -- graphite furnace atomic absorption spectrometry -- microwave sample decomposition -- humus and moss samples.


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