Moreira Pedro Nuno, de Pinho Paula Guedes, Baltazar Maria Teresa, Bastos Maria Lourdes, Carvalho Félix, Dinis-Oliveira Ricardo Jorge
North Branch, National Institute of Legal Medicine, I.P., Portugal.
Biomed Chromatogr. 2012 Mar;26(3):338-49. doi: 10.1002/bmc.1663. Epub 2011 Jun 8.
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.
百草枯（PQ）是一种与众多死亡事件相关的除草剂，主要由自愿摄入所致。已采用多种方法对中毒者血浆和尿液样本中的PQ进行定量分析，以此作为临床结果的预测指标。目前尚无经过验证的用于分析死后样本中PQ的方法。因此，本研究的目的是开发一种分析方法，即采用固相萃取后的气相色谱 - 离子阱质谱联用技术（GC - IT/MS），对死后样本（即全血、尿液、肝脏、肺和肾脏）中的PQ进行定量分析，以涵盖PQ的分布、蓄积和消除途径。该方法具有选择性，因为没有与PQ和对草快乙酯（内标）保留时间相同的内源性化合物产生干扰。PQ的回归分析在0 - 10μg/mL范围内呈线性。检测限范围从尿液中的0.0076μg/mL到全血中的0.047μg/mL，回收率适用于法医分析。所提出的GC - IT/MS方法为死后样本中PQ的定量分析提供了一种准确、简单且具有足够精密度和回收率的检测方法。在两例致命的PQ中毒案例中进行了适用性验证。还对季铵类除草剂测定的分析方法进行了综述，以便更好地了解目前可用的技术。
