Analusis 28, 850-854 (2000)
DOI: 10.1051/analusis:2000155

Comparison of dissolution methods for multi-element analysis of some plant materials used as bioindicator of sulphur and heavy metal deposition determined

R. Pöykiö¹, H. Torvela¹, P. Perämäki², T. Kuokkanen² and H. Rönkkömäki<sup>2

1</sup>  Meri-Lappi Institute, Centre for Environmental Technology, University of Oulu, Tietokatu 6, FIN-94600, Kemi, Finland
²  University of Oulu, Department of Chemistry, P.O. Box 3000, FIN-90014, University of Oulu, Finland

(Received September 12, 2000; revised November 28, 2000; accepted December 5, 2000.)

Abstract
Most analytical methods for trace element determination in plant material require decomposition of the sample. Sample decomposition procedures play an important role in ensuring that chemical analysis gives correct results. This is especially important in the determination of trace elements in plant material for environmental studies because, as a rule, plant material is not homogeneous and usually contains variable matrices. In this paper microwave digestion procedures using HNO₃, HNO₃+H₂O₂, HNO₃+HClO₄, HF mixtures and dry ashing + HF were investigated for the analysis of Al, Ca, Cr, K, Mg, Mn, Zn, S, Pb, V, Cu, Cd, Co and Ni by ICP-AES or ICP-MS from pine needle samples. Reference samples BCR CRM 100 (Spruce Needles), BCR CRM 101 (Beech Leaves) and HUMH2 (Organic surface soil) were used to test the dissolution methods. The results showed that the sample digestion procedure is critical step for obtaining accurate results. Losses of volatile metals were notable in many cases when dry ashing was used.

Key words: Plant material -- dissolution methods -- elemental analysis -- ICP-AES -- ICP-MS -- CRMs -- microwave oven.


© EDP Sciences, Wiley-VCH 2000