Identification of metabolites and thermal transformation products of quinolones in raw cow's milk by liquid chromatography coupled to high-resolution mass spectrometry.
The presence of residues of antibiotics, metabolites, and thermal transformation products (TPs), produced during thermal treatment to eliminate pathogenic microorganisms in milk, could represent a risk for people. Cow's milk samples spiked with enrofloxacin (ENR), ciprofloxacin (CIP), difloxacin (DIF), and sarafloxacin (SAR) and milk samples from cows medicated with ENR were submitted to several thermal treatments. The milk samples were analyzed by liquid chromatography-mass spectrometry (LC-MS) to find and identify TPs and metabolites. In this work, 27 TPs of 4 quinolones and 24 metabolites of ENR were found. Some of these compounds had been reported previously, but others were characterized for the first time, including lactose-conjugated CIP, the formamidation reaction for CIP and SAR, and hydroxylation or ketone formation to produce three different isomers for all quinolones studied.
Departament de Quı́mica Analı́tica, Universitat de Barcelona , Campus de l'Alimentació de Torribera, Avinguda Prat de la Riba 171, 08921 Sta. Coloma de Gramanet, Barcelona, Spain.
Alexandra
A
Junza
Sergio
S
Barbosa
M Rosa
MR
Codony
Anna
A
Jubert
José
J
Barbosa
Dolores
D
Barrón
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism; D001711:Biotransformation; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004350:Drug Residues / Q000737:chemistry* / Q000378:metabolism; D006358:Hot Temperature; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D015363:Quinolones / Q000737:chemistry* / Q000378:metabolism; D053719:Tandem Mass Spectrometry
D000900:Anti-Bacterial Agents; D015363:Quinolones