The sorption process plays an important role in the environmental fate and effect of xenobiotics in the aquatic system. The sorption coefficients (log Koc) of sixty-one organic compounds from different chemical classes such as PAHs, organochlorines, biphenyls, phenols and heterocyclic compounds to humic acid as model sorbent have been determined by batch technique combined with negligible depletion-SPME in two different modes of extraction as analytical tool and compared with literature data. The influence of pH and temperature variation was studied. Experimental log Koc data were compared...