Analytical methods for environmental detection of bis-(2-chloroethyl)sulphide and its degradation products.

摘要

Bis-(2-chloroethyl)sulphide is a strong vesicant, blister-causing agent also known as sulphur mustard or mustard gas. Sulphur mustard has been designated a Schedule 1 controlled chemical by the Chemical Weapons Convention because of its use as an incapacitating warfare agent. Physiological damage is a consequence of an intramolecular reaction that forms a reactive ethylene episulphonium ion intermediate. This intermediate reacts with cellular DNA resulting in immediate cell death and is suspected to have long-term carcinogenic effects.*;The analytical techniques for the detection of 1,4-thioxane and 1,4-dithiane both volatile organic chemicals, in soil and water were validated using purge and trap extraction followed in tandem by gas chromatographic-mass spectrometric (GC-MS) analysis. Recovery efficiencies for these compounds ranged from (104-134)% with detection limits for both matrices in the low ng-g-1 and mug·dm -3 (ppb) range in soil and water respectively.;Sulphur mustard in soil method of analysis validation was achieved by pressurized solvent extraction and in water, a liquid-liquid extraction method was used to extract the analyte prior to gas chromatographic (GC) analysis. The average recoveries for sulphur mustard from soil and water were 68% and 116% respectively.;Thiodiglycol required derivatization using N,O-bis-(trimethylsilyl) trifluoroacetamide (BSTFA) in the presence of pyridine in order to achieve suitable resolution during gas chromatographic analysis of the extract volumes. In-situ derivatization was employed prior to the extraction of thiodiglycol from soil via repeat solvent washes. For thiodiglycol in water, the drying agent, sodium sulphate, was used to eliminate the water matrix; the decahydrate formed was then washed with solvent in order to extract the analyte prior to derivatization. The average extract recoveries achieved for thiodiglycol from soil and water were 88% and 69% respectively.;Although largely prohibited, mustard gas has been used sporadically by rogue and non-signatory governments throughout the twentieth century. Terrorist threats have led to rejuvenated interest in the development of analytical methods for the analysis of mustard and its degradation products in environmental matrices. Numerous methods have been published that identify procedures for the analysis of mustard and degradation products, thiodiglycol, 1,4-thioxane and 1,4-dithiane. Few of these publications have achieved the precision or detection limits associated with conventional environmental parameters. This study investigates techniques that can obtain statistically validated detection limits for mustard and its degradation products in water and soil matrices.*;Single quadrupole and ion trap mass spectrometric detection were used to establish detection limits for sulphur mustard and thiodiglycol in soil and water. The full array of mass analyzer settings including full scan, selected ion monitoring (SIM) and tandem mass spectrometry (MS-MS) were employed to optimize the detection method for each analyte. In these experiments tandem-MS did not increase the signal-to-noise ratio and did not improve the detection limit significantly. With future research tandem-MS may prove significant in extending method detection limits below the 1 part per million levels established in the present study.;*Please refer to dissertation for diagrams.