A method using reverse-phase ultra-high-performance liquid chromatography coupled with tandem mass spectrometry is described for eight classes of therapeutants that are used in marine aquaculture products. Validation studies to evaluate recovery, precision, method detection limits, and measurement uncertainty were performed at three levels, using three representative matrices [salmon (fatty fish), tilapia (lean fish), and shrimp (crustaceans)] to assess the method performance for use as a screening or determinative (quantitative and confirmatory) method. A total of 16 sulfonamides (plus 2 potentiators), 2 tetracyclines, 11 (fluoro)quinolones, 7 nitroimidazoles, 3 amphenicols, 5 steroids, and 3 stilbenes met the quantitative criteria for method validation. An additional 5 triphenylmethane dyes, 2 sulfonamides, 2 tetracyclines, and 1 amphenicol met the required performance for use as a screening method. Limits of detection (LODs) for the compounds that met the quantitative criteria ranged from 0.1 to 5 μg/kg, while LODs for compounds from the screening group ranged from 0.1 to 30 μg/kg. This method provides a comprehensive approach to the determination of different classes of compounds in aquaculture products.
Keywords: LC−MS/MS; crustaceans; fish; growth promoters; multi-class methods; multi-residue methods; veterinary drug residues.