title: Quantification of nerve agent biomarkers in human serum and urine.
abstract: A novel method for rapid and sensitive quantification of the nerve agent metabolites ethyl, isopropyl, isobutyl, cyclohexyl, and pinacolyl methylphosphonic acid has been established by combining salting-out assisted liquid-liquid extraction (SALLE) and online solid phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS). The procedure allows confirmation of nerve agent exposure within 30 min from receiving a sample, with very low detection limits for the biomarkers of 0.04-0.12 ng/mL. Sample preparation by SALLE was performed in less than 10 min, with a common procedure for both serum and urine. Analyte recoveries of 70-100% were obtained using tetrahydrofuran as extraction solvent and Na2SO4 to achieve phase separation. After SALLE, selective analyte retention was obtained on a ZrO2 column by Lewis acid-base and hydrophilic interactions with acetonitrile/1% CH3COOH (82/18) as the loading mobile phase. The phosphonic acids were backflush-desorbed onto a polymeric zwitterionic column at pH 9.8 and separated by hydrophilic interaction liquid chromatography. The method was linear (R(2) ≥ 0.995) from the limits of quantification to 50 ng/mL, and the within- and between-assay repeatability at 20 ng/mL were below 5% and 10% relative standard deviation, respectively.
authors.affiliation: Norwegian Defence Research Establishment , P.O. Box 25, NO-2027 Kjeller, Norway.
authors.forename: Bent Tore
authors.initials: BT
authors.lastname: Røen
authors.forename: Stig Rune
authors.initials: SR
authors.lastname: Sellevåg
authors.forename: Elsa
authors.initials: E
authors.lastname: Lundanes
mesh_terms: D015415:Biomarkers / Q000097:blood / Q000652:urine; D006801:Humans; D009946:Organothiophosphorus Compounds / Q000097:blood* / Q000652:urine*
chemical_list: D015415:Biomarkers; D009946:Organothiophosphorus Compounds