title: Preparation of stable isotope-labeled 2-nitrobenzaldehyde derivatives of four metabolites of nitrofuran antibiotics and their comprehensive characterization by UV, MS, and NMR techniques.
abstract: A convenient method is presented for the preparation of the carbon-13-labeled 2-nitrobenzaldehyde derivatives of the nitrofuran metabolites 3-amino-2-oxazolidinone (AOZ), semicarbazide (SC), 1-aminohydantoin (AH), and 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), with the purpose of using them as internal standards for the quantification of trace levels of nitrofuran residues by liquid chromatography-tandem mass spectrometry in foods of animal origin. The synthesis encompasses the nitration of [1,2,3,4,5,6-(13)C(6)]toluene prior to chromyl compound-mediated oxidation of the methyl group into the corresponding aldehyde. The four metabolites of nitrofuran antibiotics were derivatized independently with the resulting ring-labeled 2-nitrobenzaldehyde (NBA) to obtain the target compounds. Both the isotopically enriched and native substances were used to perform a comprehensive fragmentation study by electrospray ionization (ESI) collision-induced dissociation (CID) mass spectrometry (MS). Full characterization of the nitrofuran derivatives was accomplished with ultraviolet (UV) and exhaustive nuclear magnetic resonance (NMR) analysis. A major advantage of the described procedure is that it can be extended to the preparation of other carbon-13-labeled derivatives of metabolites of nitrofuran antibiotics.
authors.affiliation: Nestlé Research Center, Nestec Ltd., Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland. thierry.delatour@rdls.nestle.com
authors.forename: Thierry
authors.initials: T
authors.lastname: Delatour
authors.forename: Eric
authors.initials: E
authors.lastname: Gremaud
authors.forename: Pascal
authors.initials: P
authors.lastname: Mottier
authors.forename: Janique
authors.initials: J
authors.lastname: Richoz
authors.forename: Francia
authors.initials: F
authors.lastname: Arce Vera
authors.forename: Richard H
authors.initials: RH
authors.lastname: Stadler
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001547:Benzaldehydes / Q000737:chemistry*; D002247:Carbon Isotopes; D006827:Hydantoins / Q000737:chemistry; D007553:Isotope Labeling / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D009581:Nitrofurans / Q000378:metabolism*; D023303:Oxazolidinones / Q000737:chemistry; D012663:Semicarbazides / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000900:Anti-Bacterial Agents; D001547:Benzaldehydes; D002247:Carbon Isotopes; D006827:Hydantoins; D009581:Nitrofurans; D023303:Oxazolidinones; D012663:Semicarbazides; C010059:carbamylhydrazine; C043850:2-nitrobenzaldehyde; C000209:3-amino-2-oxazolidinone