Los cient\u00edficos que trabajan en el Dugway Proving Ground del ej\u00e9rcito de los EE. UU. han desarrollado un nuevo m\u00e9todo para el an\u00e1lisis de agentes de guerra qu\u00edmica (CWA) con tubos absorbentes s\u00f3lidos (SST). “T\u00e9cnicas como esta, que pueden detectar agentes de guerra qu\u00edmica en niveles m\u00e1s bajos, ayudan a garantizar una mejor calidad de las pruebas y nos brindan capacidades que antes no ten\u00edamos”.<\/p>\n
Scientists working at the U.S. Army\u2019s Dugway Proving Ground have developed a new method for solid sorbent tube (SST) analysis of chemical warfare agents (CWA).<\/p>\n
The innovative approach is to analyze an eluate from the SST using a Gas Chromatography Triple Quadrople Mass Spectrometry (GC-QQQ) instead of thermally analyzing the SST using a Gas Chromatography \u2013 Flame Photometric Detector (GC-FPD).<\/p>\n
The GC-QQQ is a highly sensitive instrument. Chemists Jeremy Jex, Hannah Line and Travis Losser, with the help of Dr. Richard Phan, Chemical Analytical Branch Chief, took on the extensive work to successfully develop quantitative methods for ultratrace analysis of traditional CWA, such as nerve agents GA, GB, GD, GF and VX and mustard (HD) blister agent.<\/strong><\/p>\n The group had to develop acquisition models for the new instrument, including the method detection limit and the limit of quantification, for each chemical agent. They validated their standards and quality control samples, running a calibration curve on the GC-QQQ to determine the instrument\u2019s official limits. Once that was completed, the group conducted CWA recover efficiency studies from the elution for each agent. The elution method pulls the solvent through the SST to extract CWA into a vial.<\/strong><\/p>\n \u201cThe extracted CWA from the elution were found to be around 96 percent efficient,\u201d shared Line. \u201cTechniques like this that can detect chemical warfare agents at lower levels help ensure better quality of testing and give us capabilities we didn\u2019t have previously.\u201d <\/strong><\/p>\n Additional benefits of using the GC-QQQ include ease of operation and increased output because it bypasses the need for a confirmation\/transfer tube, since the mass spectrometer is the confirmation.<\/p>\n \u201cWe wanted to get away from thermal desorption using GC-FPD because it is labor intensive and can\u2019t be automated so it requires an analyst to be with the instruments the whole time,\u201d said Jex. \u201cThis new extraction method is much less labor intensive.\u201d The GC-QQQ coupled with an autosampler allows up to 150 samples to be sequentially analyzed in one completely unattended run<\/strong>, \u201cincreasing productivity and providing time to work on data packages instead of manually inserting transfer tubes one by one,\u201d Jex noted.<\/p>\n Instead of a transfer tube, the new elution method provides another advantage. \u201cThe solvent can be stored and reanalyzed with various instrumentation and multiple analyses,\u201d<\/strong> said Losser, who created the methodology for the new extraction process. \u201cWith the thermal desorption method, there is no remaining sample for reanalysis. It\u2019s a one-and-done analysis.\u201d
\nNow that chemists Jex, Line, Losser and Phan have proven the GC-QQQ is a viable method for chemical warfare agent analysis, it can be used to support future tests. The group will present their findings in early March during a virtual chemical analytical technical conference.<\/p>\n