title: A novel approach to modeling the reaction kinetics of tetracycline antibiotics with aqueous ozone.
abstract: Tetracycline antibiotics represent one of the most successful classes of pharmaceuticals and are extensively used around the world for human and veterinary health. Ozone-based processes have emerged as a selective water treatment process for many pharmaceuticals. The primary objective of this study was to determine the reaction kinetics for transformation of five tetracycline antibiotics (i.e., chlortetracycline, doxycycline, oxytetracycline, rolitetracycline, and tetracycline) by ozone across the pH2 to 9 range. The apparent second-order rate constant for tetracycline was on the order of 1-6 × 10(4) M(-1) s(-1) at low pH, and 0.6-2.0 × 10(6) M(-1) s(-1) at near neutral pH. The apparent second-order rate constants did not fit a conventional pKa-based model, presumably due to the complex acid/base speciation of tetracycline antibiotics. A model that considers the net charge on tetracycline molecules in solution provided a nice fit to experimental data for all five tetracyclines. The five tetracycline antibiotics demonstrated similar reaction kinetics with ozone, and a cumulative analysis of all kinetics data provides a baseline model for other tetracycline compounds. The ozone exposure required for complete transformation of tetracycline antibiotics (10(-5) M-s) is well below that achieved during ozone disinfection processes (10(-3) M-s), indicating that ozone is an effective treatment for tetracycline antibiotics.
authors.affiliation: Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, ECS 314, Baltimore, MD 21250, USA.
authors.forename: Zachary R
authors.initials: ZR
authors.lastname: Hopkins
authors.forename: Lee
authors.initials: L
authors.lastname: Blaney
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D015394:Molecular Structure; D010126:Ozone / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D013752:Tetracycline / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D014874:Water Pollutants, Chemical; D010126:Ozone; D013752:Tetracycline
keywords: Antibiotics; CA; CTC; Chlortetracycline; DAD; DC; DI; ESI; HPLC; MS/MS; OTC; Oxytetracycline; Ozone; RTC; Reaction kinetics; TC; TET; Tetracycline; WWTP; chlortetracycline; cinnamic acid; deionized water; diode array detector; doxycycline; electrospray ionization; high performance liquid chromatography; oxytetracycline; rolitetracycline; t-BuOH; tandem mass spectrometry; tert-butanol; tetracycline; tetracycline antibiotics; wastewater treatment plant