Abstract

ZAMORA-MARTINEZ, Olivia et al. SUITABILITY AND COMPARISON OF SPECTROSCOPIC TECHNIQUES FOR THE ANALYSIS OF GEOLOGICAL SAMPLES. Rev. Int. Contam. Ambient [online]. 2019, vol.35, n.1, pp.65-79.  Epub Aug 21, 2020. ISSN 0188-4999.  https://doi.org/10.20937/rica.2019.35.01.05.

Four analytical methodologies for the determination of chemical species of environmental interest were optimized and adapted. By means of the flame atomic absorption spectroscopy technique (FAAS) it was possible to sequentially quantify Fe, Mn, Cu, Cr, Ni, Pb, and Zn concentrations in sediment, soil and rock samples. Through the formation of colorful complexes of iron species, obtained under specific and well-defined reaction conditions, and their subsequent quantification by visible spectroscopy with independent methodologies, it was possible to determine the total iron, Fe2+ and Fe3+ content in mine leachates. The methodologies described turned out to be precise and accurate, they are free of matrix interferences and are comparable with other validated methodologies. The linearity intervals in FAAS for the seven elements vary from 0.05 to 16 mg/L, with detection limits between 0.03 and 0.2 mg/L. With respect to the colorimetric determinations of total Fe, Fe2+ and Fe3+ in samples of sulfided mining leachates, linear ranges of concentration comprised between 0.05 and 17.5 mg/L were observed. The detection limits obtained were 0.05 mg/L for total Fe and Fe2+ and 0.14 mg/L for Fe3+.

Keywords : analytical spectroscopy; suitability of methods; rocks; soils; sediments; mine leached.