Characterization of AOX by fractionation analysis and size-exclusion chromatography

A characterization method for AOX in surface water samples was developed an d tested. The method involves fractionation using a hydrophobic C18 resin a nd a weak anionic exchange resin and allows the fractionation of the AOX po ol of surface water samples into four fractions: (1) hydrophilic acidic, (2 ) hydrophilic non-acidic, (3) hydrophobic acidic, and (4) hydrophobic non-a cidic. The adsorption analysis was verified with AOX-relevant model compoun ds and was applied to characterize the AOX pool of a stream sample from the Moskva river (Russia). In addition to the fractionation analysis, size-exc lusion chromatography was used to characterize the AOX pool of the sample s tudied. Hydrophilic acids made up the major fraction of the AOX pool (55%). Among this fraction chlorinated high-molecular acids (humic substances) ma de up the main fraction (35%).