Evaluation of the toxicity of imidacloprid in wild birds. A new high performance thin layer chromatography (HPTLC) method for the analysis of liver and crop samples in suspected poisoning cases

Several accidents were reported in France, in domestic and wild animals, in volving the potential ingestion of imidacloprid-coated seeds. Imidacloprid is a new insecticide which acts as a nicotinic blocker. Since there was ver y limited published information regarding this compound, its toxicity to wi ld birds, and potential routine analytical techniques, this study was desig ned to set up and validate a method for the detection and quantification of imidacloprid and its primary metabolite, 6-chloronicotinic acid, in tissue s and organs of affected animals. A high performance thin layer chromatogra phy (HPTLC) technique was developed to quantify both compounds. The method is repeatable, reproducible, and sensitive enough to investigate potential poisoning cases (limits of quantification between 0.25 and 0.5 mu g/g). The technique was also applied successfully to birds found dead after a kno wn exposure to the compound and indicates that imidacloprid accounts for th e majority of the toxic residues detected in the liver of affected pigeons.