Performance evaluation of commercial ELISA kits for screening of furazolidone and furaltadone residues in fish

Regulatory monitoring for nitrofuran drug residues in aquaculture products has largely focused on LC-MS/MS. In addition, there is a need for facile and high-throughput screening methods for monitoring programs. We evaluated the performance of Ridascreen (R-Biopharm) ELISA kits for nitrofuran drug residues in fish muscle, with verification by LC-MS/MS. Kits were available for 3-amino-2-oxazolidinone (AOZ) and 3-amino-5-morpholino-methyl-2-oxazolidinone (AMOZ) side-chains of furazolidone and furaltadone, respectively. We found good repeatability in fortified and incurred muscle samples, with RSDs ranging from 1.8% to 7.6%. Recoveries of AOZ and AMOZ from muscle fortified at levels of 0.5–2 ng/g ranged from 98% to 114%. Excellent selectivity was demonstrated. The minimum detection limits (MDLs) for AOZ and AMOZ in muscle were 0.05 and 0.2 ng/g, respectively. ELISA data were highly correlated with those of LC-MS/MS. Results of this study support the use of these kits as screening assays for nitrofuran residues in fish muscle.