lewisite and n-butyl-mercaptan

A rapid, sensitive and robust method for determining the chemical warfare agents Lewisites and their hydrolysis products in aqueous and multiphase sample matrices has been developed as an extension of the previous work (Terzic, 2010 [32]). In the new method, the acidification of the sample and use of 1-butanethiol derivatisation instead of trimethylsilylation significantly improved both, qualitative and quantitative aspects of targeted analysis of Lewisite species. The limit of detection was ≤100ng/ml in full scan MS, with sample volume of 10μl only. The whole sample preparation procedure took 9min, while the gas chromatography (GC)-mass spectrometry (MS) analysis cycle was under 22min. The method deals efficiently with the multiphase sample matrices offering a fast and simple alternative to the conventional approach of liquid-liquid extraction combined with derivatisation. Multiphase sample matrices can be encountered or formed when preparing environmental, industrial, waste or decontamination waste samples for a GC-MS analysis. The applicability and robustness of the method were demonstrated by the successful analysis of 11 years old OPCW Official Proficiency Test sample and a triphase liquid sample. The same equipment set-up, tubes and derivatising agent have been used for collection, preparation and analysis of Lewisites in air samples (Terzic et al., 2012 [35]). The minimal logistic requirements, ease of operation, versatility and other features aforementioned, make this method an excellent choice for an environmental or forensic field laboratory.

Topics: Arsenicals; Chemical Warfare Agents; Equipment Design; Gas Chromatography-Mass Spectrometry; Hydrolysis; Limit of Detection; Solid Phase Extraction; Sulfhydryl Compounds

Thermal desorption with gas chromatography-mass spectrometry (TD-GC-MS) remains the technique of choice for analysis of trace concentrations of analytes in air samples. This paper describes the development and application of a method for analysing the vesicant compounds sulfur mustard and Lewisites I-III. 3,4-Dimercaptotoluene and butanethiol were used to spike sorbent tubes and vesicant vapours sampled; Lewisite I and II reacted with the thiols while sulfur mustard and Lewisite III did not. Statistical experimental design was used to optimise thermal desorption parameters and the optimum method used to determine vesicant compounds in headspace samples taken from a decontamination trial. 3,4-Dimercaptotoluene reacted with Lewisites I and II to give a common derivative with a limit of detection (LOD) of 260 microg m(-3), while the butanethiol gave distinct derivatives with limits of detection around 30 microg m(-3).

Topics: Arsenicals; Chemical Warfare Agents; Drug Stability; Gas Chromatography-Mass Spectrometry; Hot Temperature; Mustard Gas; Sensitivity and Specificity; Sulfhydryl Compounds; Toluene