Validation of a Rapid Quantitative Method for the Residues of Nitrofuran Metabolites in Loach by Accelerated Solvent Extraction and HPLC Triple Quadrupole Mass Spectrometry

Abstract

A rapid method using HPLC-MS/MS has been developed for quantitative determination of the metabolites of nitrofurans, namely 3-amino-2-oxazolidone (AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone (AMOZ), 1-ammino-hydantoin (AHD) and semicarbazide (SEM) in loach. The extraction procedure was founded on simultaneous acidic hydrolysis and derivatization using 2-nitrobenzaldehyde (2-NBA) for 1 hour at 50℃, followed by purification with liquid-liquid extraction. Recovery was evaluated by spiking standards into blank samples at three levels (0.5, 1.0 and 2.0 ?g/kg), and the mean recovery was 75.1 ? 108.1%. Precision values expressed as the relative standard deviation (%RSD) were ≤ 8.7% and ≤ 8.5% for intra-day and inter-day precision, respectively. Linearity was studied in the range of 0.2 ? 20 μg/Kg for NBAOZ, 0.8 ? 20 μg/Kg for NBAMOZ, 0.2 ? 20 μg/Kg for NBAHD, and 0.1 ? 20 μg/Kg for NBSEM, and the obtained coefficient correlations (r) were ≥ 0.99 for all compounds. Limits of detection (LODs) for the derivatized nitrofuran metabolites were established at 0.06 μg/Kg for NBAOZ, 0.24 μg/Kg for NBAMOZ, 0.06 μg/Kg for NBAHD, and 0.03 μg/Kg for NBSEM. Limits of quantification (LOQs) were established at 0.2 μg/Kg for NBAOZ, 0.8 μg/Kg for NBAMOZ, 0.2 μg/Kg for NBAHD, and 0.1 μg/Kg for NBSEM. This simplified rapid method for reducing the derivatization and hydrolysis times can be applied to the determination of nitrofuran residues in loach.