title: Method for determination of pentobarbital in dry dog food by gas chromatography/mass spectrometry.
abstract: A procedure has been developed and validated for measuring the concentration of pentobarbital residues in dry, extruded animal feed in the range of 3-200 ng/g (ppb) with an estimated limit of quantitation of 2 ppb. The method was developed for surveillance purposes: to measure the concentration of euthanizing agent which might be present in feeds incorporating rendered products which themselves might include some fraction of euthanized animals. A previously published qualitative procedure was modified by adding isotopically labelled pentobarbital as an internal standard. Dry feed was ground and extracted with methanol. The extract was loaded on a mixed-mode (C-18, anion exchange) solid-phase extraction cartridge designed for barbiturate residues. Pentobarbital was eluted and derivatized for gas chromatography/mass spectrometry in positive ion chemical ionization mode. Quantitation was based on the ratio of dimethyl-pentobarbital MH+ (m/z 255) vs dimethyl-pentobarbital-d(5) (m/z 260) in standards and extracts. Accuracy ranged from 112% at 3 ppb to 96% at 200 ppb, with relative standard deviations ranging from 4% at 3 ppb to 2% at 200 ppb.
authors.affiliation: Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, Maryland 20708, USA. dheller@cvm.fda.gov
authors.forename: D N
authors.initials: DN
authors.lastname: Heller
authors.forename: K M
authors.initials: KM
authors.lastname: Lewis
authors.forename: W
authors.initials: W
authors.lastname: Cui
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001688:Biological Products; D004285:Dogs; D005065:Euthanasia / Q000662:veterinary; D005504:Food Analysis / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D008460:Meat; D008903:Minerals; D010424:Pentobarbital / Q000032:analysis*; D012680:Sensitivity and Specificity
chemical_list: D001688:Biological Products; D008903:Minerals; D010424:Pentobarbital; C027762:bone meal