Colorimetric Gas Detection Tubes: Limits of Detection and Evaluation Using Active Chemical Warfare Agents

Chemical weapons continue to be an ongoing threat thatnecessitatesthe improvement of existing detection technologies where new technologiesare absent. Lower limits of detection will facilitate early warningof exposure to chemical weapons and enable more rapid deployment ofcountermeasures. Here, we evaluate two colorimetric gas detectiontubes, developed by Draeger Inc., for sarin and sulfur mustard chemicalwarfare agents and determine their limits of detection using activechemical agent. Being that commercial companies are only able to usechemical agent simulants during sensor development, it is imperativeto determine limits of detection using active agent. The limit ofdetection was determined based on the absence of a reasonably perceptiblecolor response at incrementally lower concentrations. A chemical vaporgenerator was constructed to produce stable and quantifiable concentrationsof chemical agent vapor, with the presence of chemical agent verifiedand monitored by a secondary detector. The limits of detection ofthe colorimetric gas detection tubes were determined to be 0.0046 & PLUSMN; 0.0002 and 2.1 & PLUSMN; 0.3 mg/m(3) for sarin and sulfurmustard, respectively. The response of the sarin detection tube wasreadily observable with little issue. The sulfur mustard detectiontube exhibited a weaker response to active agent compared to the simulantthat was used during development, which will affect their conceptof operations in real-world detection scenarios.

Automated summary

Chemical weapons pose a continuous threat and require improved detection technologies, especially in the absence of new technologies. Lower detection limits can provide early warning and enable rapid countermeasure deployment. This study evaluated colorimetric gas detection tubes for sarin and sulfur mustard warfare agents, determining their limits of detection using active chemical agent. Results showed detection limits of 0.0046 ± 0.0002 and 2.1 ± 0.3 mg/m(3) for sarin and sulfur mustard, respectively. The response of the sulfur mustard detection tube to active agent was weaker compared to the simulant used during development, impacting their real-world detection capabilities.