Development and Validation of a Method for the Determination of Phenylbutazone Drug Residues in Bovine, Equine, and Porcine Muscle Tissues Using HPLC with UV Detection

Abstract

A sensitive liquid chromatographic method with UV detection has been developed for the analysis of phenylbutazone (PBZ) drug residues in bovine, equine, and porcine muscle tissues. PBZ is extracted from muscle tissues with ethyl acetate/methanol solution containing DL‐dithiothreitol. The tissue extract is centrifuged, evaporated to minimum volume under nitrogen, and cleaned up on a conditioned Florisil solid phase extraction cartridge. PBZ is eluted with a 1:1 mixture of ether and a solution of methylene chloride:methanol:acetic acid (94:4:2 v/v/v). The eluate is evaporated to dryness with nitrogen, reconstituted in mobile phase, filtered, and analyzed by reversed‐phase liquid chromatography with UV detection at 270 nm. The method, with a detection limit of 3 ppb, was used to monitor the prevalence of PBZ drug residues in equine, porcine, and bovine muscle tissues obtained from animals slaughtered in federally inspected Canadian abattoirs.

Keywords:

• Phenylbutazone
• Validation
• HPLC
• UV detection

Acknowledgments

The authors would like to thank Karen Bauche, Kathleen Verity, and Becky Schurman for their skilled analytical services and the laboratory quality manager, Valerie Martz for generating the sample recognition standards.