Effect of Dissolved Organic Matter on Extraction Efficiencies

Abstract

Two techniques for the extraction of a series of organochlorine compounds (chlorinated benzenes, polychlorinated biphenyls, DDT, DDE, and mirex) from centrifuged Niagara River water were compared. The more hydrophobic compounds were extracted more efficiently by a digestion technique than by conventional hexane extraction. Plots of the relative recovery (R = undigested/digested) versus log of the octanol-water coefficient (K ow ) show R decreasing exponentially with log Kow. This decrease suggests that the digestion-extraction recovers both the dissolved fraction and the fraction bound to organic matter, although conventional solvent extraction does not recover the bound fraction efficiently. H UMIC ACIDS, FULVIC ACIDS, AND DISSOLVED ORGANIC MATTER, which arefound in all natural waters, are very complex compounds of both aquatic and terrestrial origin. Humic substances are polyelectrolytes containing both aromatic and aliphatic carbon with phenolic, alcoholic, carbonyl, acidic, and amino functional groups.