Applications of NAA, PIXE and XPS for the quantification and characterization of the humic substances/iodine association

This paper illustrates the coupling of Neutron Activation Analysis (NAA), Proton Induced X-ray Emission (PIXE) and X-ray Photoelectron Spectroscopy (XPS) to quantify iodine contents in natural humic substances from different geochemical origins and to determine its chemical environment. Non negligible contents of iodine from some hundreds of μg/g to more than one weight per cent have been quantified in the humic substances, and iodine seems to be attached to the organic matter by covalent bonds.