Capillary gas chromatographic analysis of nerve agents using large volume injections

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Forensic Science

Background:

• Organophosphorus chemical warfare agents (CWAs) pose significant environmental and health risks.
• Accurate detection of intact CWAs in water samples is crucial for verification and response.
• Previous methods using ethyl acetate for large volume injections encountered detection challenges.

Purpose of the Study:

• To develop and validate a new analytical procedure for the sensitive detection of intact organophosphorus CWAs in water.
• To evaluate alternative solvents to overcome detection issues associated with ethyl acetate.
• To assess the stability of CWAs in water samples under specific pH conditions.

Main Methods:

• Development of a novel analytical procedure utilizing large volume injections.
• Evaluation of alternative solvents for improved CWA detection.
• Analysis of nerve agents (sarin, tabun, soman, DFP, VX) in freshly prepared and stored water samples.
• pH adjustment of water samples to approximately 5 shortly after sampling and to pH 7 for analysis.

Main Results:

• The developed procedure enables the determination of sarin, soman, DFP, and VX at parts-per-trillion (ppt) levels in water.
• All tested agents, except tabun, remained detectable at 20-60% levels after 8 days when samples were stored at appropriate pH.
• Successful verification of intact organophosphorus CWAs in aqueous matrices was achieved.

Conclusions:

• The new method offers a reliable and sensitive approach for detecting key organophosphorus CWAs in water.
• Proper pH control during sampling and analysis is critical for preserving the integrity of most tested nerve agents.
• This advancement aids in environmental monitoring and forensic analysis of chemical warfare agent contamination.