Abstract: The nitrofuran metabolites (AMOZ, SEM, AHD and AOZ) were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) in aquatic products. The sample pretreatment method and chromatographic conditions were optimized. The sample pH value was adjusted to 7.0~7.5 after derivation. Then the analytes were extracted by 8 mL ethyl acetate. Following centrifugation, the supernatant was transferred and evaporated to dryness under a gentle stream of nitrogen at 40 ℃. The residues were redissolved in 1 mL mobile phase of acetonitrile and 0.1% formic acid (5/95, V/V), and then centrifuged at 20 000×g for 10 min at 4 ℃. Gradient elution for LC separation was performed by using acetonitrile and 0.1% formic acid in water solution, and four nitrofuran metabolites were excellently separated with a C₁₈ column. This accurate optimized method can promote efficiency greatly and is suitable for lot determination of nitrofuran metabolites in aquatic products.