Rapid Method for the Determination and Confirmation of Fluoroquinolone Residues in Catfish Using Liquid Chromatography/Fluorescence Detection and Liquid Chromatography-Tandem Mass Spectrometry

Abstract

A simplified method for the extraction and determination of four fluoroquinolone (FQ) residues (ciprofloxacin, enrofloxacin, sarafloxacin, and difloxacin) in catfish is presented. In this method, the FQ residues were extracted with acidified acetonitrile, and the extract was defatted with dispersive C18 solid-phase extraction (SPE) sorbent or hexane. A portion of the extract was evaporated and reconstituted in the mobile phase. The quantitative determination was accomplished with LC-fluorescence detection (FLD), and the confirmation was by LC-MS/MS. Fortifications of catfish tissue were carried out at 0.5x, x, 2x, and 4x, where x = 5 ppb (U.S. Food and Drug Administration current regulatory target level). Recoveries for the LC/FLD determination of five replicates (for both cleanup routes) at each level ranged from 64 to 98, with RSD values <8. The method quantitation limits for all residues were <1 ng/g. The LC-MS/MS analysis of the same extracts confirmed all FQ residues at all levels. This method is an improvement over existing methodologies since additional cleanup steps, such as cation exchange SPE column cleanup, are not utilized. The C18 dispersive SPE method represents a novel cleanup approach for FQs in fish tissue.

Laser diode thermal desorption mass spectrometry for the analysis of quinolone antibiotic residues in aquacultured seafood

“…with acetic acid, sodium chloride, two portions of acetonitrile, and a hexane clean‐up yielded good recoveries for the quinolones from catfish . Addition of solid‐phase extraction (SPE) cartridge clean‐up with Oasis HLB phase (Waters, 60 mg), or dispersive bulk C18 clean‐up (Bondesil) in place of the hexane clean‐up, was found to decrease the LDTD matrix background response and provide a stronger signal for the quinolones. Addition of bulk C18 to the acetonitrile extract required mixing and centrifugation to remove particulates, but proved to be faster than SPE column clean‐up.…”

The pivotal role of mass spectrometry in determining the presence of chemical contaminants in food raw materials

“…LC-FLD gives better sensitivity and selectivity than LC-UV, as this technique is specific towards compounds exhibiting fluorescence properties (fluorophore). While some chemical food contaminants such as fluoroquinolones (McMullen, Schenck, & Vega, 2009) exhibit natural fluorescence properties, some other compounds require a derivatization step (addition of a fluorescent moiety) to enable detection in LC-FLD (Kijak, Jackson, & Shaikh, 1997;Vassilakis, Tsipi, & Scoullos, 1998;Dall'Asta et al, 2004). Numerous chemical contaminants have been monitored by LC-FLD such as mycotoxins (Trucksess et al, 2007), bisphenol A form PVC food packaging (Lopez-Cervantes & Paseiro-Losada, 2003), or veterinary drug residues (Ali et al, 2000;Edder et al, 2002).…”

Investigations into the performance of travelling wave enabled conventional and cyclic ion mobility systems to characterise protomers of fluoroquinolone antibiotic residues

“…[6][7][8] However tandem quadrupole MS using multiple reaction monitoring (MRM) with its selectivity/sensitivity benefits has gained widespread acceptance. [9][10][11][12] The identification acceptance criteria for this approach are defined in the European Commission Decision 2002/657/EEC, which regulates the requirements for analytical methods used to quantify and confirm VDRs in food and animal feeds. 13 When choosing to implement a new tandem quadrupole based method for VDR analysis, the selection of the most appropriate MRM transitions is critical and must be performed and validated in accordance with the 2002/657/EC guidelines.…”

“…Many different types of mass analysers are routinely utilised for veterinary drug residue (VDR) analysis, including single quadrupole, ion trap and more recently time‐of‐flight (TOF)‐based technologies . However tandem quadrupole MS using multiple reaction monitoring (MRM) with its selectivity/sensitivity benefits has gained widespread acceptance . The identification acceptance criteria for this approach are defined in the European Commission Decision 2002/657/EEC, which regulates the requirements for analytical methods used to quantify and confirm VDRs in food and animal feeds .…”