Anatomopathological and toxicological analysis of a dog poisoned with methomyl

A dog with suspected poisoning was submitted for postmortem examination. Generalised visceral congestion was observed in the abdominal cavity, with the liver, kidneys and gastrointestinal tract most severely affected. However, there was no macroscopic evidence of granular material in the gastric contents. Chromatographic analyses using liquid chromatography with diode‐array detection and gas chromatography with flame‐ionisation detection identified methomyl (MET), and the finding was confirmed by gas chromatography–mass spectrometry (GC–MS). MET is thermally unstable at high temperatures and may be partially or completely transformed into an oxime derivative with a mass‐fragmentation pattern similar to that of MET ( m / z 58, 88 and 105). However, the MET molecular ion ( m / z 162) enables unequivocal identification by GC–MS. This case report demonstrates the importance of anatomopathological examination and the correct interpretation of evidence by professionals in directing appropriate toxicological analyses, supporting public health policies aimed at combating exogenous poisoning, and enabling law‐enforcement agencies to identify offenders and enforce the law.