title: Analysis of methylphosphonic acid, ethyl methylphosphonic acid and isopropyl methylphosphonic acid at low microgram per liter levels in groundwater.
abstract: A method is described for determining methylphosphonic acid, ethyl methylphosphonic acid and isopropyl methylphosphonic acid, which are hydrolysis products of the nerve agents VX (S-2-diisopropylaminoethyl O-ethyl methylphosphonothiolate) and GB (sarin, isopropylmethyl phosphonofluoridate). The analytes are extracted from 50 ml groundwater using a solid-phase extraction column packed with 500 mg of silica with a bonded quaternary amine phase, and are eluted and derivatized with methanolic trimethylphenylammonium hydroxide. Separation and quantitation are achieved using a capillary column gas chromatograph equipped with a flame photometric detector operated in its phosphorus-selective mode. Two independent statistically-unbiased procedures were employed to determine the detection limits, which ranged between 3 and 9 micrograms/l, for the three analytes.
authors.affiliation: Organic Chemistry Section, Oak Ridge National Laboratory, TN 37831-6120, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Sega
authors.forename: B A
authors.initials: BA
authors.lastname: Tomkins
authors.forename: W H
authors.initials: WH
authors.lastname: Griest
mesh_terms: D002849:Chromatography, Gas; D006868:Hydrolysis; D007202:Indicators and Reagents; D063065:Organophosphonates / Q000032:analysis*; D009943:Organophosphorus Compounds / Q000032:analysis*; D010783:Photometry; D014881:Water Supply / Q000032:analysis*
chemical_list: D007202:Indicators and Reagents; D063065:Organophosphonates; D009943:Organophosphorus Compounds; C108318:ethyl methylphosphonic acid; C048760:isopropyl methylphosphonic acid; C032627:methylphosphonic acid