Detection of anticoagulant residues by a new HPLC method in specimens of poisoned animals and a poison control case study

Poisonings of domestic and wildlife animals are frequently caused by anticoagulants. Between 1996 and 2003, 70% of all suspected animal poisoning cases were confirmed in this laboratory following analysis of a variety of specimens. Thirty-nine percent of all animal poisonings detected in this laboratory were caused by anticoagulants. Suspicious veterinarians and pet owners involved with animal poisonings ask for toxicological analyses. With respect to these demands, a new high-performance liquid chromatography (HPLC) method (system-I, reversed-phase C-18 column, methanol/ammonium acetate) combined with specific extraction procedures was developed for the sensitive detection of nine substances with anticoagulative properties. This method yields high recoveries of the analytes, which can simultaneously be detected. In addition, another HPLC (system-II, acetonitrile/potassium phosphate) was used to confirm and separate chromatographic peaks, which could not be resolved by HPLC system-I. The reliable method has good reproducibility and is most suitable for forensic analyses. Using these analytical procedures, concentrations of eight organic anticoagulants were determined in more than 100 aliquots of animal liver, blood, bait, gastric content, bloody intestinal content, and water. Over the last eight years, dogs and wild birds were the most frequently poisoned species. Interestingly, lethally poisoned birds had lower anticoagulant residues in their organs than mammals.