Department of Chemistry

Ion Exclusion Chromatography (IEC) finds application in the separation of a wide range of small, neutral or partially ionized molecules. In IEC, the strong as well as weak electrolytes are eluted unseparated, the first at the beginning and the latter at the end of the elution. The retention volumes of the remaining electrolytes are found to be proportional to their dissociation constant values. The dead and inner volumes of the chromatographic column can be determined from the observed dependence of retention volumes on dissociation constant values. The retention mechanism is described by the analytical equations and by the results obtained from the computer simulation of the column performance (using global thermodynamic and chromatographic equations or the Craig method). The mixed retention mechanism involving hydrophobic adsorption and screening effect is observed for weak electrolytes and aromatic compounds. Aromatic compounds are found to be retained almost solely by a reverse-...

SUMMARY Cellular oxidative stress has been implicated as a key mechanism of cell differentiation provoked by several compounds (doxorubicins, fibra- des, edelfosine). Phenylacetate and its derivatives in submillimolar to mil- limolar concentrations induce cell differentiation. Ion-exclusion chroma- tography is widely used for separation and analysis of weak acids. We ap- plied it to the analysis of phenylacetic acids and to the determination of the hydroxyl radical-trapping potential of some of these compounds. Their total antioxidant potential for peroxy radicals was also measured using a photometric method. It was found that phenylacetates are weak antioxidants and in the concentrations which induce cell differentiation effects may substantially reinforce intracellular antioxidative potential.