Development and validation of a multi-substance method for routine analysis of pesticides in post-mortem samples by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

Abstract

Pesticides play an important role in forensic toxicology and are usually classified as a single class of chemicals. Despite their commonly perceived unity, pesticides encompass a spectrum of compounds, including organophosphates, carbamates, pyrethroids or organochlorines, among others, each with varying degrees of toxicity. Pesticide analysis in post-mortem samples can be difficult due to the complexity of the samples and to the high toxicity of these compounds. The aim of this study was to develop and validate an easy to use, sensitive, and robust method, using ultra-performance liquid chromatography-tandem mass spectrometry to be incorporated in the routine flow for pesticide analysis in post-mortem blood samples. Described herein is a streamlined, expeditious, yet highly efficient method facilitating the screening, qualitative assessment, and quantitative confirmation of 15 pesticides, including acetamiprid, azinphos-ethyl, bendiocarb, carbofuran, chlorfenvinphos, dimethoate, imidaclopride, malathion, methiocarb, methomyl, parathion, pirimicarb, strychnine, tetrachlorvinphos, and thiacloprid in post-mortem blood, recognizing the pivotal role blood plays in forensic investigations. The developed method was linear from 10 to 200 ng/mL; limits of detection were between 1 and 10 ng/mL, depending on the compound; it was successfully evaluated a dilution ratio of 1–2, 5 and 10; and 8 substances showed maximum stability for the time interval studied. This UHPLC-MS/MS method is useful and a powerful tool in a toxicology lab because it is fast, simple, effective, and trustworthy. The results of this validation highlight the robustness of the analytical method, providing a valuable tool for the accurate and sensitive detection of pesticides in post-mortem blood. Poised for routine implementation, this method has already found success in suspected intoxication cases, promising to elevate the standards of forensic pesticide analysis.