Gas Chromatography/Mass Spectrometry in Analysis of Chemicals Related to the Chemical Weapons Convention

Author(s):  
Eric R. J. Wils
2019 ◽  
Vol 26 (3) ◽  
pp. 213-224
Author(s):  
A Veeresham ◽  
M Sandeep ◽  
T Jagadeshwar Reddy ◽  
A Suresh Pal ◽  
K Srinivas ◽  
...  

Screening of chemicals related to chemical weapons convention including their all possible degradation and reaction products in environmental samples is important in the organization for prohibition of chemical weapons verification process. Sulfur mustards, commonly known as blistering agents, are included in schedule 1 chemicals of chemical weapons convention. Because of the presence of chlorine atoms in sulfur mustards, they are highly reactive and prone to react with other organic molecules such as phenols to produce corresponding reaction products. Thus, it is important to screen for not only the sulfur mustards but also their reaction products for verification process. The sulfur mustards and their degradation products have been routinely analyzed by gas chromatography/mass spectrometry method, however, the methods are yet to establish for the reaction products. In this study, the reaction products of the sulfur mustards with phenol (compounds 1–7) were studied by gas chromatography/mass spectrometry under electron ionization and chemical ionization conditions. The EI spectra of 1–7 displayed molecular ion and characteristic fragments that provided structure information. Mostly the fragment ions were due to homolytic cleavages involving C–O, C–S, and C–C cleavages. The methane or isobutane CI spectra showed M+., [M + H]+, and [M − H]+ ions including reagent specific adduct ions. The CI spectra also showed other adduct ions formed by association of analyte molecule with its most abundant fragment ion. The gas chromatography/retention index values were also calculated, which support unambiguous identification of targeted molecules in suspected environmental samples. The method was demonstrated for detection of the targeted molecules spiked in soil samples.


2018 ◽  
Vol 24 (6) ◽  
pp. 442-453 ◽  
Author(s):  
T Sony ◽  
L Sridhar ◽  
L Sai Sachin ◽  
VVS Lakshmi ◽  
S Prabhakar

N-Alkylaminoethanols, N,N′-dialkylaminoethanols, and triethanolamine are the hydrolyzed products or precursors of V-agents/nitrogen mustards. These compounds are prone to undergo oxidation in environmental matrices. Detection of the oxidized products provides a clue for the presence of parent amine compounds and it is an important task in the verification process of chemical weapons convention. Gas chromatography/mass spectrometry is the technique of choice for the detection of most of the chemical warfare agents; however, it is ideal to develop gas chromatography/mass spectrometry techniques for all the possible degradation products of chemical warfare agents as well. In general, the N-oxides of amines are expected to be thermally unstable; hence, the gas chromatography/mass spectrometry analysis of the N-oxides of triethanolamine, N-alkyldiethanolamines and N,N′-dialkylaminoethanols is not explored. In this study, the N-oxides of chemical weapons convention-related aminoethanols (13 compounds) were successfully silylated and then analyzed by gas chromatography/mass spectrometry under electron ionization and chemical ionization techniques. The electron ionization mass spectra showed abundant molecular ions and structure indicative fragment ions including [M-(O+CH2CH2OH)]+. The alkyl groups attached to nitrogen resulted in structure-specific fragment ions that enable differentiation of isomeric compounds. The methane/chemical ionization spectra showed considerably abundant [M+H]+ (>10%) and the expected adduct ions. The retention indices of all the compounds were calculated using Van den Dool's formula. The gas chromatography/mass spectrometry data together with retention index values could be used for unambiguous identification of the N-oxides of aminoethanols during off-site analysis or proficiency tests.


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