The combination of RO concentration and XAD-8/XAD-4 resin adsorption techniques was used to isolate the different constituents of the Natural Organic Matter (NOM) from inorganic salts. NOM fractions i.e. colloids, hydrophobic NOM (HPO humic substances), transphilic NOM (TPI) and hydrophilic NOM (HPI) fractions isolated from different surface waters were characterized using 13C NMR and FT-IR spectroscopy and HPLC/Size Exclusion Chromatography coupled with UV and DOC detection. Results showed that the isolation procedure was suitable to quantitatively isolate the different fractions of NOM.