Analytical Sciences

Preliminary Studies of Iron Speciation (Fe²⁺ and Fe³⁺) in Peat Samples Using Polarography

Paavo PERAMAKI,   Mia KUMPUMAKI, Ilkka VALIMAKI, and Ritva HEIKKINEN

Department of Chemistry, University of Oulu, PO. Box 3000, FIN-90401 Oulu, Finland

Current-sampled (tast) polarography was used in the determination of the two iron oxidation states Fe²⁺ and Fe³⁺ in peat samples. The iron couple was reversible in the 0.1 mol L^-1 citrate-supporting electrolyte used. The total iron concentration in the samples was determined by differential pulse polarography. Sample decomposition was done in a nitrogen atmosphere by hydrofluoric acid and sulfuric acid. The accuracy of the determinations was verified by spiking experiments and analyzing in-house standards (Geological Survey of Finland) RS 31 (Rapakivi granite), RS 71 (Diabase) and certified reference material PCC-1 (Peridotite, U.S. Geological Survey). The method, developed for this purpose, proved to be reasonably accurate.

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