MOIETY-SPECIFIC OXIDATION REACTIONS AND CONSEQUENT CHANGES IN BIOCHEMICAL ACTIVITIES OF ANTIBACTERIAL COMPOUNDS DURING AQUEOUS OZONATION PROCESSES

摘要

Ozone (O3) reacts rapidly with a limited variety of chemical functional groups including double bonds, activated aromatic rings, amino groups and thiols. Such functional groups are found in various combinations within many of the antibacterial compounds known to be released in significant amounts to aquatic environmental systems. In many cases such structural moieties are also relevant to the biological activity exhibited by antibacterial compounds. The present investigation has been undertaken to evaluate the use of ozone to selectively “deactivate” such biologically active compounds via targeted oxidation of structural moieties critical to their biological activity. The pH-dependent variations in the magnitudes of k_(app,O3) were modeled according to each substrate’s acid-base speciation patterns to facilitate determination of species-specific reactivities toward O3. Structural analogues of the targeted functional moieties in each antibacterial structure were used to determine moiety-specific reactivities. Microbiological assays were used to measure the residual antibacterial potencies remaining after treatment of parent antibacterial compounds with increasing doses of ozone. Results obtained from experiments involving sulfamethoxazole, trimethoprim, ciprofloxacin and triclosan are presented here.