Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS

Valdez, Carlos A.; Leif, Roald N.; Hok, Saphon; Vu, Alexander K. K.; Salazar, Edmund P.; Alcaraz, Armando

doi:10.1016/j.scitotenv.2019.05.205

Title: Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS

Abstract

A practical and efficient protocol for the derivatization and detection by GC-EI-MS of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, key diagnostic degradation products of the nerve agents sarin, soman and cyclosarin respectively, in six different types of soil matrices is presented here. The method involves the in situ conversion of the phosphonic acids to their respective methyl esters using trimethyloxonium tetrafluoroborate when present in the soils at low levels (10 μg g⁻¹) without any prior extractions or soil preparation. The soils employed in our study were Nebraska EPA soil, Georgia soil, silt, Virginia type A soil, regular sand and Ottawa sand and were chosen for their vast differences in composition and physical features. Appealing attributes of the protocol include its rapidity (t < 30 min), mildness (ambient temperature), and practicality that includes the production of the phosphonic methyl esters that can be easily detected by GC-EI–MS and corroborated with the instrument's internal NIST spectral library or the Organisation for the Prohibition of Chemical Weapons (OPCW) central analytical database (OCAD v.21_2019). The overall efficacy of the protocol was then tested on a soil sample featured in the 44th OPCW PT that our laboratory participated in. After preparing the soil so as to give pinacolyl methylphosphonic acid atmore »« less

Authors:

^[1]; Leif, Roald N. ^[1]; Hok, Saphon ^[1]; Vu, Alexander K. K. ^[1]; Salazar, Edmund P. ^[1]; Alcaraz, Armando ^[1]

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: Thu May 16 00:00:00 EDT 2019

Research Org.:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1635457

Alternate Identifier(s):: OSTI ID: 1532782

Report Number(s):: LLNL-JRNL-768457; LLNL-JRNL-786457
Journal ID: ISSN 0048-9697; 957674

Grant/Contract Number:: AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Science of the Total Environment

Additional Journal Information:: Journal Volume: 683; Journal ID: ISSN 0048-9697

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Chemical Warfare Agents; Sarin; Soman; Cyclosarin

Citation Formats


                    Valdez, Carlos A., Leif, Roald N., Hok, Saphon, Vu, Alexander K. K., Salazar, Edmund P., and Alcaraz, Armando. Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS.  United States: N. p., 2019. 
Web.  doi:10.1016/j.scitotenv.2019.05.205.

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                    Valdez, Carlos A., Leif, Roald N., Hok, Saphon, Vu, Alexander K. K., Salazar, Edmund P., & Alcaraz, Armando. Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS.  United States.  https://doi.org/10.1016/j.scitotenv.2019.05.205

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                    Valdez, Carlos A., Leif, Roald N., Hok, Saphon, Vu, Alexander K. K., Salazar, Edmund P., and Alcaraz, Armando. Thu .  
"Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS".  United States.  https://doi.org/10.1016/j.scitotenv.2019.05.205.  https://www.osti.gov/servlets/purl/1635457.

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@article{osti_1635457,

  title        = {Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS},

  author       = {Valdez, Carlos A. and Leif, Roald N. and Hok, Saphon and Vu, Alexander K. K. and Salazar, Edmund P. and Alcaraz, Armando},

  abstractNote = {A practical and efficient protocol for the derivatization and detection by GC-EI-MS of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, key diagnostic degradation products of the nerve agents sarin, soman and cyclosarin respectively, in six different types of soil matrices is presented here. The method involves the in situ conversion of the phosphonic acids to their respective methyl esters using trimethyloxonium tetrafluoroborate when present in the soils at low levels (10 μg g−1) without any prior extractions or soil preparation. The soils employed in our study were Nebraska EPA soil, Georgia soil, silt, Virginia type A soil, regular sand and Ottawa sand and were chosen for their vast differences in composition and physical features. Appealing attributes of the protocol include its rapidity (t < 30 min), mildness (ambient temperature), and practicality that includes the production of the phosphonic methyl esters that can be easily detected by GC-EI–MS and corroborated with the instrument's internal NIST spectral library or the Organisation for the Prohibition of Chemical Weapons (OPCW) central analytical database (OCAD v.21_2019). The overall efficacy of the protocol was then tested on a soil sample featured in the 44th OPCW PT that our laboratory participated in. After preparing the soil so as to give pinacolyl methylphosphonic acid at a 5 μg g–1 concentration, the acid was successfully methylated and detected by GC-EI-MS. The protocol's performance mirrors that of the universally employed diazomethane protocol but accomplishes this without any of the explosive hazards and time consuming reagent preparation commonly associated with it.},

  doi          = {10.1016/j.scitotenv.2019.05.205},

  journal      = {Science of the Total Environment},

  number       = ,

  volume       = 683,

  place        = {United States},

  year         = {Thu May 16 00:00:00 EDT 2019},

  month        = {Thu May 16 00:00:00 EDT 2019}

}

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https://doi.org/10.1016/j.scitotenv.2019.05.205

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Cited by: 20 works

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Figure 1: Reaction between a G-based nerve agent and acetylcholinesterase (AChE) resulting in the formation of adducted (inhibited) AChE. Reactivation by oxime antidotes generates the AChE, while hydrolysis of the adducted AChE complex resulting in the removal of the complex’s alkoxy side chain generates aged AChE, which cannot be reactivatedmore »

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