3-Amino-2-oxazolidinone(AOZ) standard

This report describes an enzyme-linked immunosorbent assay (ELISA) for tissue-bound metabolite 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) and the application to residue analysis in cultured fish samples. The residue is monitored as a marker for the drug furaltadone. The assay enables the detection of protein bound AMOZ in the form of a 2-nitrophenyl derivative (2-NP-AMOZ) in sample supernatant or extract after acid hydrolysis and derivatization with o-nitrobenzaldehyde. Polyclonal rabbit antibodies were produced with a new immunogen hapten, 2-NP-HXA-AMOZ. The new ELISA had adequate analytical sensitivity (IC50 value 0.325 mu g kg(-1); limit of detection 0.1 mu g kg(-1)) to determine a trace of AMOZ residue and had a high selectivity. Recoveries of AMOZ fortified at the levels of 0.1, 0.5 and 1.0 mu g kg(-1) ranged from 89.8 to 112.5% with coefficients of variation of 12.4-16.2% over the range of AMOZ concentrations studied. The results obtained with the ELISA correlated well with those obtained by commercial test kits for 150 tested samples (r=0.984). The results suggest that the developed ELISA is a highly specific, accurate, and sensitive method suitable for high throughput screening for AMOZ residues.

A high performance liquid chromatography-tandem mass spectrometric method was established for simultaneous determination of the nitrofuran metabolites, furazolidone, furaltadone, nitrofurazone and nitrofurantoin in milk powder. Protein-bound metabolites were released in HCl solution and derivatised with 2-nitrobenzaldehyde (2-NBA) overnight at 37 degrees C. Proteins were sedimentated by ZnSO4 and K-4 Fe ( CN) (6), after adjusting pH to 7. 0. Then the analytes were extracted by ethyl acetate and cleaned up by n-hexane. Identification was achieved by electrospray ionization in positive mode ( ESI+) using multiple reaction monitoring (MRM). The quantification was performed with internal standards. The recoveries of 5-methylmoipholino-3-amino-2-oxazolidinone ( AMOZ), 3-amino-2-oxazolidinone ( AOZ), semicarbazide ( SEM) and 1-amino-hydantoin (AHD) were in the range of 89.5% similar to 110.3% with spiked levels of 0.5 similar to 2 mu g/kg. The RSDs were less than 11.3%. The limits of detection were 0. 05 mu g/kg for AMOZ and AOZ; and 0. 1 mu g/kg for SEM and AHD.