A multiresidue screen for the analysis of toxicants in bovine rumen contents

Analysis of rumen contents is helpful in solving poisoning cases when ingestion of a toxic substance by cattle or other ruminant animals is suspected. The most common technique employs extraction of the sample with organic solvent followed by clean-up method(s) before analysis with gas chromatography–mass spectrometry equipped with a library of mass spectra to help identify unknowns. A rapid method using magnesium sulfate, primary secondary amine, and C18 sorbents following principles of QuEChERS to clean up rumen contents samples is reported herein. The method was validated to analyze fortified bovine rumen contents to detect commonly found organophosphorus pesticides, carbamates, and several other compounds such as atropine, 4-aminopyridine, caffeine, scopolamine, 3-chloro-4-methylaniline, strychnine, metaldehyde, and metronidazole. For each compound, the ratio of 2 ions from the mass spectrum was monitored in fortified rumen contents. The ion ratio of fortified sample was compared with the ion ratio of standard sample spectrum and was found to be within 20%, with the exception of aldicarb and 4-aminopyridine with ion ratio of 26% and 29%, respectively. Usefulness of the method was demonstrated by not only analyzing bovine rumen contents but also canine and avian gastrointestinal contents submitted for organic chemical screening.