Detection and identification of hydrolysis products of sulfur mustards at trace levels in environmental samples using liquid chromatography solid phase extraction combined with off-line nuclear magnetic resonance analysis

Abstract

An LC-UV-SPE NMR method for the analysis of polar hydrolysis products of the chemical warfare agents known as sulfur mustards at low ppm levels in environmental samples is developed. The hydrolysis products thiodiglycol (I), bis(2-hydroxyethylthio)methane (II), 1,2-bis(2-hydroxyethylthio)ethane (III), 1,3-bis(2-hydroxyethylthio)propane (IV), 1,4-bis(2-hydroxyethylthio)butane (V), 1,5-bis(2-hydroxyethylthio)pentane (VI), bis(2-hydroxymethylthioethyl)ether (VII) and bis(2-hydroxyethylthioethyl)ether (VIII) are baseline separated within 11min by the LC gradient program and trapped post-column on SPE cartridges. After elution in 2mm o.d. NMR tubes 1H NMR spectra were recorded. Recoveries vary from 43±5 for I to 102±5% for VI and are limited by volume breakthrough. The detection limits of the LC-SPE NMR method vary between 200ng for V and 450ng for I. Increasing the injection volume is shown to be more effective than multiple trapping for the analytes I–VIII to increase the amount of material trapped on the SPE cartridges. The applicability of the developed method to the analysis of environmental samples was tested by the analysis of sample 293 provided by the 29th Official OPCW (Organization for the Prohibition of Chemical Weapons) Proficiency Test. The chromatographic and 1H NMR data obtained by the method are highly reproducible and provide acceptable data for the identification of chemicals related to CWC (Chemical Weapons Convention) in case an off-site analysis for the verification of the CWC or OPCW Proficiency Tests according to the OPCW criteria for the acceptance of chromatographic and 1H NMR spectral data.