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In situ speciation of trace Fe(II) and Fe(III) in atmospheric waters by the FZ method coupled to GFAAS analysis

2007; Taylor & Francis; Volume: 87; Issue: 9 Linguagem: Inglês

10.1080/03067310701297837

1029-0397

Émilie Journet, Karine Desboeufs, Alexandra Sofikitis, Gilles Varrault, Jean‐Louis Colin,

Groundwater and Isotope Geochemistry

Abstract A quasi-on-line method of measurement of the oxidation states of iron coupled with a GFAAS analysis is reported for the trace conditions found in atmospheric waters. This technique is based on the formation of a specific complex [Fe(FZ)3]4− between Fe(II) and ferrozine (FZ). tC18 solid-phase extraction cartridges (Sep-Pak) are used to separate the [Fe(FZ)3]4− and Fe(III) so as to limit the risk of redox evolution of the sample. The adaptation to dilute aqueous media, via acidification at pH = 2 of rainwater sample, and atmospheric interferences are discussed, and the Fe(II) recovery in rainwaters is determined. This method coupled with a quasi-on-line sampling protocol has been tested on rains collected in Guadeloupe Island (Caribbean Sea, 16°N, 61°W) during a field campaign in May 2005. Our results show that the proposed method can satisfactorily be applied to the determination of Fe(II) and Fe(III) in atmospheric waters under in situ conditions. Keywords: Iron oxidation stateFerrozine methodRainwater samplingAtomic absorption spectrometry Acknowledgements The authors thank Dr Petit and Dr Jacoby-Koaly from the University of Guadeloupe for their help during the field measurement in Guadeloupe. Thanks to Mr Bonhomme, Institut National de la Recherche Agronomique (INRA), for allowing us to carry out our sampling on the INRA site in Petit Bourg in Guadeloupe.