Trace determination of sulphur mustard and related compounds in environmental samples by headspace-trap GC-MS

Abstract

New methods for trace determination of sulphur mustard (HD) by headspace-trap GC-MS have been developed for water and soil samples. As HD is unstable, especially in water, methods for determination of some of the cyclic decomposition compounds have also been investigated. Several parameters showed to influence the detection of the compounds, and statistical experimental design was applied to optimise instrumental parameters of the methods. Furthermore, it was found that salt saturation of the water samples and addition of salt saturated water to the soil samples improved the recovery of all analytes considerably, and in particular of HD.

The developed methods made it possible to determine HD in water and soil at the ppb level. For soil samples, this was an improvement in sensitivity by two orders of magnitude compared to literature values. The present technique showed to be even more sensitive for the cyclic decomposition compounds, with detection limits at sub-ppb level.

The headspace-trap extraction technique requires almost no sample preparation, and the total sample handling time was less than one hour for determination of the analytes in water as well as in soil samples. This is a great improvement compared to the prevailing procedures using solvent extraction, which requires several hours sample handling time.

The application of the method was demonstrated by analysing an environmental sample known to contain several HD related compounds. All compounds were found at a signal to noise level higher than what was obtained with solvent extraction. In addition, one HD related sulphur compound that had not been detected previously was found.

In the present work, it is concluded that the headspace-trap GC-MS technique has a great potential for determination of HD and HD related compounds in environmental samples.