Abstract:The method for determination of metabolites of four nitrofuran antibiotics, nitrofurantoin (AMOZ), furaltadone (SEM), nitrofurazone (AHD) and furazolidone (AOZ) in aquatic products was developed by solid-phase extraction coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). Methods Samples with isotope internal standard solutions were hydrolyzed by HCl and derivatized with 2-nitrobenzaldehyde. The analytes were cleaned up on HLB solid-phase column and eluted with ethyl acetate, then evaporated and dried with nitrogen gas. The extract components were separated and gradient eluted on a XTerra C18 column with acetonitrile-5 mmol/L ammonium acetate of 0.1% formic acid solutions ion, and simultaneously quantified by the isotope internal standard operating in positive ion under multiple reactions monitoring mode. Results The limits of quantification ranged from 0.10 μg/kg to 0.30 μg/kg for four nitrofuran metabolites. The standard curves were linear in the range of 0.5-25 μg/kg,with the correlation coefficients>0.995. The average recoveries for nitrofuran metabolites were 81.0%-104.8%, 91.0%-110.3%, 85.0%-111.4%, 88.0%-108.2% respectively, and their relative standard deviation varied between 2.7% and 14.5%. The method was applied to analyze 180 fish samples from Guangdong region, four of which were confirmed to contain AOZ ranging from 1.3 to 3.6 μg/kg. Conclusion The method developed was selective, sensitive and accurate, completely suitable for nitrofuran metabolites trace analysis in aquatic products.