title: Quantification of paraquat in postmortem samples by gas chromatography-ion trap mass spectrometry and review of the literature.
abstract: Paraquat (PQ) is an herbicide implicated in numerous fatalities, mainly caused by voluntary ingestion. Several methods have been used to quantify PQ in plasma and urine samples of intoxicated humans as a predictor of clinical outcome. There is no validated method for the analysis of PQ in postmortem samples. Therefore, the aim of this study was to develop an analytical method, using gas chromatography-ion trap mass spectrometry (GC-IT/MS) after solid-phase extraction, to quantify PQ in postmortem samples, namely in whole blood, urine, liver, lung and kidney, to cover the routes of distribution, accumulation and elimination of PQ. The method proved to be selective as there were no interferences of endogenous compounds with the same retention time as PQ and ethyl paraquat (internal standard). The regression analysis for PQ was linear in the range 0-10 µg/mL. The detection limits ranged from 0.0076 µg/mL for urine to 0.047 µg/mL for whole blood, and the recoveries were suitable for forensic analysis. The proposed GC-IT/MS method provided an accurate and simple assay with adequate precision and recovery for the quantification of PQ in postmortem samples. The proof of applicability was performed in two fatal PQ intoxications. A review of the analytical methods for the determination of quaternary ammonium herbicides is also provided for a better understanding of the presently available techniques.
authors.affiliation: North Branch, National Institute of Legal Medicine, I.P., Portugal.
authors.forename: Pedro Nuno
authors.initials: PN
authors.lastname: Moreira
authors.forename: Paula Guedes
authors.initials: PG
authors.lastname: de Pinho
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Baltazar
authors.forename: Maria Lourdes
authors.initials: ML
authors.lastname: Bastos
authors.forename: Félix
authors.initials: F
authors.lastname: Carvalho
authors.forename: Ricardo Jorge
authors.initials: RJ
authors.lastname: Dinis-Oliveira
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D010269:Paraquat / Q000097:blood / Q000378:metabolism* / Q000652:urine; D011180:Postmortem Changes
chemical_list: D010269:Paraquat