Suitable extraction of soils and sediments for mercury species and determination combined with the cold vapor generation atomic absorption spectrometry technique

Abstract

This work reports a fast and efficient procedure for mercury species extraction using Universol® as extractor reagent in soil and sediment samples combined with the cold vapor generation atomic absorption spectrometry (CV AAS) technique. Hg total was determined after oxidation CH3Hg+ to Hg2+ with KMnO4 and reduction Hg2+ to Hg0 with NaBH4. To ensure specificity and sensitivity in the Hg2+ determination, L-cysteine was added before the reduction with SnCl2 to form complex with organic mercury species. Recovery values of between 98 and 102% were obtained for Hgtotal, and 96–100% for Hg2+. The relative standard deviations were lower than 2.7%. The detection limits were 0.07 and 0.08mgkg−1 for Hgtotal and Hg2+, respectively. The use of Universol® reagent combined with the CV AAS technique proved to be a simple and efficient procedure for the determination of Hgtotal and Hg2+ in soil and sediment samples without interconversion of species allowing chemical speciation studies.