title: Determination of flumequine in channel catfish by liquid chromatography with fluorescence detection.
abstract: Rapid methods are described for determination of flumequine (FLU) residues in muscle and plasma of farm-raised channel catfish (Ictalurus punctatus). FLU residues were extracted from tissues with an acidified methanol solution, and extracts were cleaned up on C18 solid-phase extraction cartridges. FLU concentrations were determined by liquid chromatography (LC) using a C18 analytical column and fluorescence detection (excitation, 325 nm; emission, 360 nm). Mean recoveries of FLU from fortified muscle were 87-94% at 5 levels ranging from 10 to 160 ppb (5 replicates per level). FLU recoveries from fortified plasma were 92-97% at 5 levels ranging from 20 to 320 ppb. Limits of detection (signal-to-noise ratio, 3:1) for the method as described were 3 and 6 ppb for muscle and plasma, respectively. Relative standard deviations (RSDs) for recoveries were < or = 12%. Live catfish were dosed with 14C-labeled or unlabeled FLU to generate incurred residues. Recoveries of 14C residues throughout extraction and cleanup were 90 and 94% for muscle and plasma, respectively. RSDs for incurred FLU at 2 levels in muscle and plasma ranged from 2 to 6%. The identity of FLU in incurred tissues was confirmed by LC/mass spectrometry.
authors.affiliation: U.S. Food and Drug Administration, Gulf Coast Seafood Laboratory, Dauphin Island, AL 36528, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Plakas
authors.forename: K R
authors.initials: KR
authors.lastname: el Said
authors.forename: F A
authors.initials: FA
authors.lastname: Bencsath
authors.forename: S M
authors.initials: SM
authors.lastname: Musser
authors.forename: C C
authors.initials: CC
authors.lastname: Walker
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000032:analysis* / Q000097:blood; D002250:Carbon Radioisotopes; D002853:Chromatography, Liquid / Q000379:methods*; D004350:Drug Residues / Q000032:analysis; D024841:Fluoroquinolones; D006863:Hydrogen-Ion Concentration; D007059:Ictaluridae; D000432:Methanol; D009132:Muscles / Q000737:chemistry; D011786:Quality Control; D011807:Quinolizines / Q000032:analysis* / Q000097:blood; D013050:Spectrometry, Fluorescence
chemical_list: D000890:Anti-Infective Agents; D002250:Carbon Radioisotopes; D024841:Fluoroquinolones; D011807:Quinolizines; C012976:flumequine; D000432:Methanol