title: Determination of nifursol metabolites in poultry muscle and liver tissue. Development and validation of a confirmatory method.
abstract: A method is described for the identification and quantitative determination of 3,5-dinitrosalicylic acid hydrazide (DSH), the marker residue of nifursol metabolites in poultry (turkey, broiler) muscle and liver tissue. The method is based on the acid-catalysed hydrolysis of tissue-bound metabolites to free DSH and in situ derivatisation with 2-nitrobenzaldehyde to the corresponding nitrophenyl derivative NPDSH. A structural analogue of DSH, 4-hydroxy-3,5-dinitrobenzoic acid hydrazide (HBH) was synthesised to serve as an internal standard. The analytes were isolated from the matrix by liquid-liquid extraction with ethyl acetate. Determination was performed by LC-MS/MS with negative electrospray ionisation. The [M - H](+) ions of NPDSH and NPHBH at m/z 374 were fragmented by collision induced dissociation (CID) producing transition ions at m/z 182, 183 and 226. The transition ions at m/z 182 and 226 were selected for monitoring of NPDSH while the transition ion at m/z 183 was selected for NPHBH. The method has been validated according to the EU criteria of Commission Decision 2002/657/EC at 0.5, 1.0 and 1.5 microg kg(-1) in muscle and liver tissue. A decision limit (CC(alpha)) was obtained of 0.04 and 0.025 microg kg(-1) in muscle and liver, respectively. Similarly a detection capability (CC(beta)) was obtained of 0.10 and 0.05 microg kg(-1) in muscle and liver, respectively. The introduction of HBH as an internal standard did not lead to a significant improvement of the quantitative performance of the method. In fact for liver better performance characteristics were obtained when the IS was not taken into account. Nevertheless, as a qualitative marker for recovery, HBH could still be very useful in the analysis of unknown samples.
authors.affiliation: RIKILT-Institute of Food Safety, Bornsesteeg 45, P.O. Box 450, 6700 AE Wageningen, The Netherlands. patrick.mulder@wur.nl
authors.forename: P P J
authors.initials: PP
authors.lastname: Mulder
authors.forename: T
authors.initials: T
authors.lastname: Zuidema
authors.forename: N G M
authors.initials: NG
authors.lastname: Keestra
authors.forename: P J F
authors.initials: PJ
authors.lastname: Kooij
authors.forename: I J W
authors.initials: IJ
authors.lastname: Elbers
authors.forename: J A
authors.initials: JA
authors.lastname: van Rhijn
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods; D004350:Drug Residues / Q000032:analysis*; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D008099:Liver / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D009132:Muscles / Q000737:chemistry; D009581:Nitrofurans / Q000378:metabolism*; D011200:Poultry / Q000378:metabolism*
chemical_list: D000981:Antiprotozoal Agents; D009581:Nitrofurans; C032119:nifursol