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

Chemical weapons continue to be an ongoing threat that necessitates the improvement of existing detection technologies where new technologies are absent. Lower limits of detection will facilitate early warning of exposure to chemical weapons and enable more rapid deployment of countermeasures. Here, we evaluate two colorimetric gas detection tubes, developed by Draeger Inc., for sarin and sulfur mustard chemical warfare agents and determine their limits of detection using active chemical agent. Being that commercial companies are only able to use chemical agent simulants during sensor development, it is imperative to determine limits of detection using active agent. The limit of detection was determined based on the absence of a reasonably perceptible color response at incrementally lower concentrations. A chemical vapor generator was constructed to produce stable and quantifiable concentrations of chemical agent vapor, with the presence of chemical agent verified and monitored by a secondary detector. The limits of detection of the colorimetric gas detection tubes were determined to be 0.0046 ± 0.0002 and 2.1 ± 0.3 mg/m³ for sarin and sulfur mustard, respectively. The response of the sarin detection tube was readily observable with little issue. The sulfur mustard detection tube exhibited a weaker response to active agent compared to the simulant that was used during development, which will affect their concept of operations in real-world detection scenarios.