Degradation of fluoroquinolone antibiotics and identification of metabolites/transformation products by liquid chromatography-tandem mass spectrometry

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Alexandra S. Maia (Author) Other; Ana R. Ribeiro (Author) FEUP; Catarina L. Amorim (Author) Other; Juliana C. Barreiro (Author) Other; Quezia B. Cass (Author) Other; Paula M. L. Castro (Author) Other; Maria Elizabeth Tiritan (Author) FFUP

Journal

Title: Journal of Chromatography A

Vol. 1333

Pages: 87-98

ISSN: 0021-9673

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 93 Citations

Scopus - 106 Citations

Other information

Authenticus ID: P-009-63K

DOI: 10.1016/j.chroma.2014.01.069

Abstract (EN): Antibiotics are a therapeutic class widely found in environmental matrices and extensively studied due to its persistence and implications for multi-resistant bacteria development. This work presents an integrated approach of analytical multi-techniques on assessing biodegradation of fluorinated antibiotics at a laboratory-scale microcosmos to follow removal and formation of intermediate compounds. Degradation of four fluoroquinolone antibiotics, namely Ofloxacin (OFL), Norfloxacin (NOR), Ciprofloxacin (CPF) and Moxifloxacin (MOX), at 10 mg L-1 using a mixed bacterial culture, was assessed for 60 days. The assays were followed by a developed and validated analytical method of LC with fluorescence detection (LC-FD) using a Luna Pentafluorophenyl (2) 3 pm column. The validated method demonstrated good selectivity, linearity (r(2) > 0.999), intra-day and inter-day precisions (RSD < 2.74%) and accuracy. The quantification limits were 5 mu g L-1 for OFL, NOR and CPF and 20 mu g L-1 for MOX. The optimized conditions allowed picturing metabolites/transformation products formation and accumulation during the process, stating an incomplete mineralization, also shown by fluoride release. OFL and MOX presented the highest (98.3%) and the lowest (80.5%) extent of degradation after 19 days of assay, respectively. A representative number of samples was selected and analyzed by LC-MS/MS with triple quadrupole and the molecular formulas were confirmed by a quadruple time of flight analyzer (QqTOF). Most of the intermediates were already described as biodegradation and/or photodegradation products in different conditions; however unknown metabolites were also identified. The microbial consortium, even when exposed to high levels of FQ presented high percentages of degradation, never reported before for these compounds.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12