Trace determination of sulphur mustard and related compounds in water by headspace-trap gas chromatography-mass spectrometry

A method for trace determination of sulphur mustard (HD) and some of its cyclic decomposition compounds in water samples has been developed using headspace-trap in combination with gas chromatography-mass spectrometry (GC-MS). Factorial design was used for optimisation of the method. The trap technology allows enrichment and focusing of the analytes on an adsorbent, hence the technique offers better sensitivity compared to conventional static headspace. A detection limit of 1 ng/ml was achieved for HD, while the cyclic sulphur compounds 1,4-thioxane, 1,3-dithiolane and 1,4-dithiane could be detected at a level of 0.1 ng/ml. The method was validated for the stable cyclic compounds in the concentration range from the limit of quantification (LOQ: 0.2-0.4 ng/ml) to hundred times LOQ. The within and between assay precisions at hundred times LOQ were 1-2% and 7-8% relative standard deviation, respectively. This technique requires almost no sample handling, and the total time for sampling and analysis was less than 1 h. The method was successfully employed for muddy river water and sea water samples.