Unambiguous identification of thiouracil residue in urine collected in non-treated bovine by tandem and high-resolution mass spectrometry.
Thyrostats are banned compounds in Europe since 1981 (directive 81/602/EC) because of their carcinogenic and teratogenic properties. However, the occurrence of thiouracil (TU) in bovine urines from national monitoring plans with quantifications in the range 1-10 microg . L(-1) occasionally raises the question of its origin which might either be the consequence of an illegal administration or the result of 'endogenous' production. In order to definitively and unambiguously identify the so-called thiouracil signal in non-treated bovine urines, independent mass spectrometry (MS) approaches have been used. Different reagents (3-IBBr, 3-BrBBr and PFBBr) were used to derivatise and to extract TU from urine samples and characterisation of the residues was performed by means of different MS approaches [LC/(ESI-)MS/MS, GC/(EI+)MS/MS and HRMS (EI and NCI)]. These combined strategies allowed for an independent and confident identification of TU in bovine urine samples collected from animals never treated with any thyrostatic drugs. This result is of prime importance for laboratories and risk managers involved in the field of forbidden growth promoters control: detection of TU residue in bovine urine will have to be carefully considered as a non-systematic proof of illegal administration.
Pinel
Gaud
G
Laboratoire d'Etude des Résidus et Contaminants dans les Aliments, Ecole Nationale Vétérinaire de Nantes, Route de Gachet, BP 50707, 44307 Nantes Cedex 3, France. laberca@vet-nantes.fr
Maume
Daniel
D
Deceuninck
Yoann
Y
Andre
François
F
Le Bizec
Bruno
B
D000383:Agriculture / Q000379:methods; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods*; D013889:Thiouracil / Q000032:analysis* / Q000737:chemistry*; D016482:Urinalysis / Q000379:methods*
D013889:Thiouracil