Detection and analysis of the carbamate distribution by DESI mass spectometry in formalin fixed and paraffin embedded tissues of intoxicated animals

Abstract

Carbamates are acetylcholinesterase inhibitors with many different formulations and uses. Aldicarb and carbofuran, originally formulated for agricultural use, are frequently employed to cause abortions, homicides, suicides and intoxications of domestic and wild animals. They are known as "small lead" due to its dark granular presentation, are offered to animals with food (bait) in a single quickly lethal dosage. When found alive, these animals present clinical signs related to the inhibition of the acetylcholinestesase enzyme, which stimulates muscarinic and nicotinic receptors, such as diarrhea, vomits, depression and convulsions. The macroscopic and histopathological changes are considered unspecific; such are blood ingurgitation in many organs. The diagnosis is obtained after the analysis of samples taken during necropsy and the most used methods are the thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and the recently validated High-performance liquid chromatography-diode array detection (HPLC-DAD). The method of desorption electrospray ionization mass spectrometry (DESI-MS) can also be used. In this technique, a solvent is directed towards a sample surface to desorb and ionize the material, which will be evaporated. Using a software, the sample is scanned and the information correlated with the spatial distribution of the chemical specimen. This method will allow the diagnosis of carbamate intoxications in cases which the fresh samples are not available. (AU)