Determination of hexavalent chromium in aqueous and alkaline soil extracts


Abstract: A fast, simple, and reliable method for determination of hexavalent chromium species in soil aqueous and alkaline extracts has been developed. The procedure is based on the ion-pair extraction of Cr(VI) with methyltrioctylammonium chloride (Aliquat 336) into xylene. The extract is analyzed by flame (FAAS) or electrothermal atomic absorption spectrometry (ETAAS). The method allows the detection of up to 2 mg kg$^{-1}$ Cr(VI) by FAAS and up to 25 $\mu $g kg$^{-1}$ Cr(VI) by ETAAS. The relative standard deviation varied in the range 2%-12% depending on the Cr(VI) levels in the samples. The analysis of certified reference material CRM041-30G Chromium VI--Soil and spike experiments showed recoveries from 91% to 106%. The procedure was applied to industrially polluted soils.

Keywords: Soil, liquid phase extraction, Cr(VI), flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry

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