Selective and sensitive chromogenic and fluorogenic detection of sulfur mustard in organic, aqueous and gaseous medium
We present a highly selective and sensitive detection protocol for the chemical warfare agent sulfur mustard (SM). The chromogenic and fluorogenic system uses a squaraine dye (SQ) that not only detects SM but also discriminates it from other chemical warfare agents (CWAs) and potent electrophilic interferents. A water soluble dithiol, 2-(3,5-bis(mercaptomethyl)phenoxy)acetic acid 1, in the presence and absence of SM, behaves differently towards the squaraine dye (SQ) to give different chromogenic and fluorogenic responses. With an aim to mimic real-life scenarios for the onsite and offsite detection, the sensing protocol was further implemented in spiked water and soil samples, on surfaces, and in the gas phase. The lower detection limit (much lower than the lethal dose) of both visual inspection and the fluorescence technique will be highly useful to mankind in order to sensitively detect SM.