PW08 Ecotoxicity and Environmental Chemistry of Antibiotics
Exhibit Hall
8:00 AM - Wednesday, 12 November 2003
(PW142) Investigations on the microbial degradability of tetracycline antibiotics and their degradation pathway employing liquid chromatography-ion trap mass spectrometry.
Eichhorn, P.1, Aga, D.1, 1 SUNY Buffalo, Chemistry Department, Buffalo, NY, United States
ABSTRACT- Broad-spectrum tetracycline antibiotics, comprising the compounds tetracycline, oxytetracycline, chlortetracycline and doxycycline are commonly used worldwide as veterinary medicines and feed additives. Their occurrence in both the aquatic and terrestrial environment in connection with the detection of bacterial resistances has led to increasing concern regarding human health. Despite the many efforts made so far for enhancing the understanding on the behavior and fate of tetracyclines in the environment, a large gap of knowledge still exists with respect to their microbial degradability and in particular to their metabolic pathway. In the present work, the biodegradation of selected tetracyclines in a lab-scale bioreactor, simulating the conditions in surface waters, is described. Liquid chromatography coupled to electrospray-ion trap-mass spectrometry (LC-ESI-MS) is used to track the primary degradation of the target analytes spiked at environmentally relevant concentrations, while somewhat higher concentrations are used for the detection of novel metabolites. Performing data-dependent experiments for the automatic detection of degradates as well as multiple-stage MS (MSn) of identified degradation intermediates allows for structural elucidation. The influence of previous exposure of the microbial community on the degradation kinetics and the role of the test concentration are investigated in further experiments carried out in the bioreactor.
Key words: microbial degradation, antibiotics, structure elucidation, ion trap-mass spectrometry