Determination of residues of nitrofuran metabolites in Litopenaeus vannamei by UPLC-MS/MS

Four nitrofuran metabolites, including semicarbazide (SEM), 1-amino-hydantoin (AHD), 3-amino-2-oxazolidinone (AOZ) and 5-methylmorpholino-3-amino-2-oxazolidinone (AMOZ) in Litopenaeus vannamei, were determined by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). SEM-13C-15N2, AHD-13C3, AOZ-D4 and AMOZ-D5 were selected as internal standard substances; the samples were derived by 2-nitrobenzaldehyde, extracted with ethyl acetate and cleaned up with n-hexane. Four targeted compounds were completely separatedwithin 8 minutesby gradient elution of methanol and 0.5 mmolL-1 ammonium acetate including 0.1% fomic acid, and they have good linear relation within 0.4~20.0 ngmL-1(R＞0.999), the limit of detection being 0.03~0.15 gkg-1. The recovery is 92.0%~107.3% (n=6) and the relative standard deviation is 3.1%~8.7% at 0.5 gkg-1, 1.0gkg-1and 2.0 gkg-1. The method achieved satisfactory result in the FAPAS (Food Analysis Performance. Assessment Scheme) International Proficiency Testing.