Dual-responsive fluorescent sensors for the detection and discrimination of sulphur and nitrogen mustards

Mustard agents, including sulphur mustard (SM) and nitrogen mustard (NM), are chemical warfare agents that can cause blistering of the skin and mucous membranes upon contact. Although SM and NM both have dermal effects, their medical management of systemic poisoning differs significantly. A rapid and simple method for detecting and discriminating between SM and NM would be greatly valuable. We report several fluorescent sensors for the detection and differentiation of SM and NM. Among these sensors, fluorescein SN-R2-2 exhibits dual fluorescence responses: quenching with NM and enhancement with SM under 430 nm excitation, achieving rapid detection (40 s for SM and 6 min for NM) and high sensitivity (limit of detection = 1.43 μM for SM and 18.01 μM for NM). Its solvent-independent performance further provides field applicability. SN-R2-2 effectively visualised different concentrations of SM and NM in living mice. SN-R2-2 holds promise for military and public safety emergencies, enhancing chemical incident response and medical triage. To the best of our knowledge, SN-R2-2 is the first sensor for SM and NM discrimination.