title: Determination of lewisite constituents in aqueous samples using hollow-fibre liquid-phase microextraction followed by gas chromatography-mass spectrometry.
abstract: The applicability of hollow-fibre liquid-phase microextraction for extracting 2-chlorovinyldichloroarsine (lewisite 1), bis(2-chlorovinyl)chloroarsine (lewisite 2), tris(2-chlorovinyl)arsine (lewisite 3) and arsenic trichloride from aqueous samples is reported. Parameters affecting the extraction efficiency of these chemicals were optimised. These parameters included the type of derivatising agent, extraction solvent, derivatisation method, pH, ionic strength, stirring speed and extraction time. A linear range between 0.002 and 0.2 μg/mL was established for the lewisites with good square regression coefficients (0.9955-0.9992). Good reproducibility with relative standard deviations (RSDs) from 8 to 10% was achieved. The limit of detection was 0.002 μg/mL for the lewisites and 0.005 μg/mL for arsenic trichloride (3:1 signal-to-noise ratio). The extraction method was validated with a proficiency test sample issued by the Organisation for the Prohibition of Chemical Weapons (OPCW). The rapidity and precision of the new method should help deter against the employment of lewisite as a chemical warfare agent: its use could be confirmed easily from analysis of aqueous samples.
authors.affiliation: DSO National Laboratories, 20 Science Park Drive, Singapore, 118230, Singapore, cmeiyee@dso.org.sg.
authors.forename: M Y
authors.initials: MY
authors.lastname: Cheh
authors.forename: H C
authors.initials: HC
authors.lastname: Chua
authors.forename: F B
authors.initials: FB
authors.lastname: Hopkins
authors.forename: J R
authors.initials: JR
authors.lastname: Riches
authors.forename: C M
authors.initials: CM
authors.lastname: Timperley
authors.forename: H S Nancy
authors.initials: HS
authors.lastname: Lee
mesh_terms: D001152:Arsenicals / Q000302:isolation & purification*; D002619:Chemical Warfare Agents / Q000302:isolation & purification*; D002712:Chlorides / Q000302:isolation & purification*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D059021:Laboratory Proficiency Testing; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D009994:Osmolar Concentration; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D001152:Arsenicals; D002619:Chemical Warfare Agents; D002712:Chlorides; D013438:Sulfhydryl Compounds; D014874:Water Pollutants, Chemical; D014867:Water; C035965:lewisite; C050510:arsenic trichloride