title: Tandem capillary column gas chromatography-mass spectrometric determination of the organophosphonate nerve agent surrogate dimethyl methylphosphonate in gaseous phase.
abstract: A procedure based on capillary column gas chromatographic-mass spectrometric (GC-MS) confirmation was developed for the verification of the ubiquitous and versatile chemical and nerve agent simulant, dimethyl methyl phosphonate (DMMP; CAS# 756-79-6), from gaseous samples. This method was developed to verify low nanogram DMMP concentrations during testing of a nerve agent detection system. Standard solutions of 1, 5, 10, 50, 100, 500, and 1000ng/ml DMMP in acetonitrile were employed. Through 15 calibration curves using the 5 lowest concentrations, coefficient of determination (r(2)) values showed a mean of 0.998 (0.992-1.000). An additional 15 calibration curves likewise containing 5 concentrations of DMMP spanning 3 orders of magnitude (1, 50, 100, 500, and 1000ng/ml) yielded a mean r(2) of 0.997 (0.991-1.000). Sixty-five nitrogen diluted gaseous samples varying from 1.0 to 10.0microl in volume were analyzed and concentrations of DMMP ranging from 1 to 1000ng/ml were confirmed. An additional 35 vapor samples in UHP N(2) ranging in DMMP concentration from 5.8microg/m(3) to 1.0mg/m(3) were analyzed by increasing sample volume range to between 10.0 and 100microl. For gaseous samples with volumes>1.0microl, the lowest concentration observed was 5.8microg/m(3). The method detection limit (Appendix B of Title 40 CFR, United States) for 1.0microl autoinjected standards in acetonitrile was determined to be 0.331ng/ml. Method precision for 15 independently analyzed standards of 25ng/ml had a relative standard deviation of 1.168. This method demonstrated high linearity across a wide range of concentrations, as well as excellent sensitivity and repeatability, and proved applicable to other lower alkyl-phosphonates.
authors.affiliation: Texas Tech University, Department of Environmental Toxicology, The Institute of Environmental and Human Health, Lubbock, TX 79409-1163, USA. les.mcdaniel@tiehh.ttu.edu
authors.forename: Les N
authors.initials: LN
authors.lastname: McDaniel
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Romero
authors.forename: Jonathan
authors.initials: J
authors.lastname: Boyd
authors.forename: Gopal
authors.initials: G
authors.lastname: Coimbatore
authors.forename: George P
authors.initials: GP
authors.lastname: Cobb
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000393:Air Pollutants / Q000032:analysis; D002138:Calibration; D000697:Central Nervous System Stimulants / Q000032:analysis*; D002619:Chemical Warfare Agents / Q000032:analysis; D002849:Chromatography, Gas / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods; D005740:Gases; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D010755:Organophosphates / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000032:analysis*; D013997:Time Factors
chemical_list: D000097:Acetonitriles; D000393:Air Pollutants; D000697:Central Nervous System Stimulants; D002619:Chemical Warfare Agents; D005740:Gases; D010755:Organophosphates; D009943:Organophosphorus Compounds; C031116:dimethyl methylphosphonate; C032159:acetonitrile