Determination of N,N-Dialkylethanolamines Related to Chemical Warfare Agents as Benzylated Species in an OPCW Proficiency Test Soil Sample by Electron Ionization Gas Chromatography-Mass Spectrometry

Abstract

In the field of chemical warfare agents (CWAs), ethanolamines are important building blocks for the preparation of nerve agents belonging to the V-series such as VX and VR as well as the nitrogen-based mustards. In this work, the determination of three members in this class of Schedule 2B reportable chemicals, namely N,N-dimethylethanolamine (DMEA), N,N-diethylethanolamine (DEEA), and N,N-diisopropylethanolamine (DIEA) by electron ionization gas chromatography-mass spectrometry (EI-GC-MS) is presented. The three dialkylethanolamines were spiked in a high organic content soil matrix featured during the 45th Organization for the Prohibition of Chemical Weapons (OPCW) proficiency test (PT) at two separate concentrations each (1 and 10 µg/g separately), simulating values often encountered during these tests. The N,N-dialkylethanolamines were O-alkylated using benzyl bromide and sodium carbonate at 55 °C and were detected as their benzylated versions by electron ionization GC-MS. The benzylation of each dialkylethanolamine yielded derivatives with higher molecular weight and therefore different GC-MS profiles such as longer retention times and sharper peak chromatography relative to their unmodified counterparts. These characteristics enable the analytical chemist to detect and confirm these important CWA-related chemicals specifically in instances where they are present in low concentrations (i.e. <10 µg/g) among more abundant interferences.

Keywords:

• Benzylation
• chemical warfare agents (CWAs)
• gas chromatography-mass spectrometry (GC-MS)
• organisation for the prohibition of chemical weapons (OPCW)
• VX

Acknowledgments

The authors would like to thank Dr. Carolyn Koester and Mr. Armando Alcaraz for critical reading of the manuscript as well as engaging discussions regarding of GC-MS data acquisition and instrumentation described in this work.

Disclaimer

This document (LLNL-JRNL-859569) was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor Lawrence Livermore National Security, LLC, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or Lawrence Livermore National Security, LLC. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or Lawrence Livermore National Security, LLC, and shall not be used for advertising or product endorsement purposes.

Auspices statement

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Disclosure statement

No potential conflict of interest was reported by the authors.