Procedure for detecting and confirming pentobarbital residues in dog food by gas chromatography/mass spectrometry

J AOAC Int. 1998 Mar-Apr;81(2):359-67.

Abstract

The method described detects and confirms presence of pentobarbital residues in dry, extruded feeds at concentrations of 5-20 ppb. Dried feed is ground to a uniform powder and shaken overnight in methanol. A portion of the methanolic extract is evaporated, and the residue is reconstituted in phosphate-buffered saline. The aqueous extract is cleaned with a solid-phase extraction cartridge designed to extract barbiturate residues from biological matrixes. Dimethyl sulfoxide, tetramethylammonium hydroxide, and iodomethane are added to derivatize pentobarbital, 1,3-Dimethyl-pentobarbital is then acidified with dilute hydrochloric acid and extracted with isooctane. The organic layer is transferred and evaporated under a stream of nitrogen. The residue is reconstituted in a small volume of ethyl acetate for analysis by gas chromatography/mass spectrometry. The limit of detection is approximately 0.7 ppb. The method was validated with pentobarbital-fortified feed samples containing high concentrations of meat and bone meal.

MeSH terms

  • Alkylation
  • Animal Feed / analysis*
  • Animals
  • Dogs
  • Drug Residues / analysis*
  • Gas Chromatography-Mass Spectrometry
  • Hypnotics and Sedatives / analysis*
  • Pentobarbital / analysis*
  • Reproducibility of Results
  • Solutions

Substances

  • Hypnotics and Sedatives
  • Solutions
  • Pentobarbital