title: Analysis of nitromethane from samples exposed in vitro to chloropicrin by stable isotope dilution headspace gas chromatography with mass spectrometry.
abstract: Chloropicrin (trichloronitromethane) is a widely used soil fumigant and an old chemical warfare agent. The metabolism of chloropicrin is not well known in mammals but nitromethane has been shown to be one of its main metabolites. Here, a fast and simple headspace gas chromatography with mass spectrometry method was applied for the measurement of nitromethane from aqueous samples. The analytical method was validated using stable isotope labeled internal standard and a small sample volume of 260 μL. No conventional sample preparation steps were needed. The method was accurate (relative standard deviations ≤1.5%) and linear (R(2) = 0.9996) within the concentration range of 0.1-6.0 μg/mL. This method was used to measure nitromethane in in vitro incubations with human and pig liver cell fractions containing enzymes for xenobiotic metabolism, exposed to chloropicrin. The results indicate that the presence of glutathione is necessary for the formation of nitromethane from chloropicrin. Also, nitromethane was formed mostly in liver cytosol fractions, but not in microsomal fractions after the incubation with chloropicrin. Our results suggest that although nitromethane is not the unequivocal biomarker of chloropicrin exposure, this method could be applied for screening the elevated levels in humans after chloropicrin exposure.
authors.affiliation: VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, P.O. Box 55, FI, Finland.
authors.forename: Mia
authors.initials: M
authors.lastname: Halme
authors.affiliation: Research and Development, Centre for Military Medicine, Finnish Defence Forces, P.O Box 50, FI, Helsinki, Finland.|School of Pharmacy/Toxicology, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI, Kuopio, Finland.
authors.forename: Maija
authors.initials: M
authors.lastname: Pesonen
authors.affiliation: VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, P.O. Box 55, FI, Finland.
authors.forename: Toni
authors.initials: T
authors.lastname: Grandell
authors.affiliation: VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, P.O. Box 55, FI, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Kuula
authors.affiliation: School of Pharmacy/Toxicology, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI, Kuopio, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Pasanen
authors.affiliation: School of Pharmacy/Toxicology, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI, Kuopio, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Vähäkangas
authors.affiliation: VERIFIN, Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, University of Helsinki, P.O. Box 55, FI, Finland.
authors.forename: Paula
authors.initials: P
authors.lastname: Vanninen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002619:Chemical Warfare Agents / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity; D005260:Female; D005651:Fumigation; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity; D066298:In Vitro Techniques; D007201:Indicator Dilution Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008697:Methane / Q000031:analogs & derivatives* / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity; D009595:Nitroparaffins / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity; D010575:Pesticides / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity; D034421:Sus scrofa
chemical_list: D015415:Biomarkers; D002619:Chemical Warfare Agents; D006843:Hydrocarbons, Chlorinated; D009595:Nitroparaffins; D010575:Pesticides; C100187:chloropicrin; D008697:Methane; C008640:nitromethane
keywords: Biomarkers; Chemical weapons; Headspace; In vitro exposure; Trichloronitromethane