LIQUID-CHROMATOGRAPHIC DETERMINATION OF OXYTETRACYCLINE IN EDIBLE FISH FILLETS FROM 6 SPECIES OF FISH

The approved use of oxytetracycline (OTC) in U.S. aquaculture is limit ed to specific diseases in salmonids and channel catfish. OTC may also be effective in controlling diseases in other fish species important to public aquaculture, but before approved use of OTC can be augmented , an analytical method for determining OTC in fillet tissue from multi ple species of fish will be required to support residue depletion stud ies. The objective of this study was to develop and validate a liquid chromatographic (LC) method that is accurate, precise, and sensitive f or OTC in edible fillets from multiple species of fish. Homogenized fi llet tissues from walleye, Atlantic salmon, striped bass, white sturge on, rainbow trout, and channel catfish were fortified with OTC at nomi nal concentrations of 10, 20, 100, 1000, and 5000 ng/g. In tissues for tified with OTC at 100, 1000, and 5000 ng/g, mean recoveries ranged fr om 83 to 90%, and relative standard deviations (RSDs) ranged from 0.9 to 5.8%. In all other tissues, mean recoveries ranged from 59 to 98%, and RSDs ranged from 3.3 to 20%. Method quantitation limits ranged fro m 6 to 22 ng/g for the 6 species. The LC parameters produced easily in tegratable OTC peaks without coelution of endogenous compounds. The me thod is accurate, precise, and sensitive for OTC in fillet tissue from 6 species of fish from 5 phylogenetically diverse groups.