Determination of nitrofurans metabolites residues in aquatic products by ultra-performance liquid chromatography-tandem mass spectrometry

A method was described for monitoring four nitrofuran metabolites including 5-methylmorpholino-3-amino-2-oxazolidinone (AMOZ), 3-amino-2-oxazolidone (AOZ), 1-amino-hydantoin (AHD) and semicarbazide (SEM) in aquatic products. The analytes were quantified by ultra-performance liquid chromatography-tandem mass spectrometry operating in positive ion multiple monitoring mode (MRM) after 2-nitrobenzaldehyde derivatization. The matrix calibration curve was established with correlation coefficient (R(2)>0.99) in the range of 1-100 ng ml(-1). Limit of detection and limit of quantification for all analytes were 0.5 and 1.5 μg kg(-1), respectively. Recovery rates and relative standard deviations ranged from 88% to 112% and 2% to 4%, respectively. The validated method was successfully applied to detect nitrofuran metabolites in 120 fish samples. The analytes were detected in 6/16 species of fish samples, with a total detection rate of 6.5%. AOZ was most frequently detected (8.3%), followed by AMOZ (7.5%), AHD (5.0%) and SEM (5.0%). The method is proposed for monitoring nitrofuran metabolites in aquatic products.