Alginite, mined at Pula (Hungary) is used as a model material. It has been originated from biomass of fossil algae during several millions of years in volcanic craters. Its organic material content is about 5-50%. It was fractionated by alkaline extraction. The solute pH was adjusted to 7, 5 and 2 respectively to produce samples for investigation. The extract was handled by microfiltration (Millipore, Durapore, 0.45 mum). The humic acid content was subdivided into those components by adsorption on Merck LiChrolut solid phase extraction cartridges: RP8 and RP18. Each separated fraction was characterized by chemical oxygen demand (COD) and RP HPLC.