A highly specific colorimetric detection of sulfur mustard and nitrogen mustard at room temperature with iodine–starch system

Abstract

In this investigation, we have developed a novel, selective, and cost-effective colorimetric detection of blister agents e.g., sulfur mustard and nitrogen mustard. This protocol enables the detection at room temperature using ‘everyday reagents’ such as sodium thiosulfate, iodine, and starch. The sensing method utilizes sodium thiosulfate as a receptor and the combination of iodine and starch as an indicator, resulting in a colorimetric response to both mustard agents. The method offers selective detection of these chemical agents over relevant interferences such as nerve agents’ simulant, acylating agent, and alkylating agent. Furthermore, the analyses of these agents in the contaminated environmental samples and Na₂S₂O₃-coated silica gel suggest that this testing technique can be directly applied to real-time investigation. We have also determined the limit of detection for SM and NM to be 0.02 mg visually, and 0.002 mg spectroscopically, both of which are below levels harmful to human skin. This highlights the potential utility and safety of our approach for detecting CW agents in diverse scenarios.