A cyanine-based probe for sensitive and selective detection of mustard gas simulant CEES

A novel cyanine dye-based probe, Cy3CS, was developed and evaluated for the detection of 2-chloroethyl ethyl sulfide (CEES), a simulant for sulfur mustard which is a notorious chemical warfare agent. The probe demonstrated a substantial (as high as 106-fold) fluorescence enhancement upon reaction with CEES even at low concentrations (0.1–1 mM and 0–100 μM). The detection displayed excellent linear correlation between fluorescence intensity and CEES concentration with high R² values (0.9954 and 0.9993 for 0.1–1 mM and 0–100 μM, respectively) and low detection limit (0.44 μM). Meanwhile, the detection does not involve base or other additives, which could simply the detection procedure. The selectivity experiments revealed that the probe responded exclusively to CEES among a range of potential interferents, proving the superior specificity. This selectivity is crucial for accurate detection in complex environments, such as soil samples, which were effectively analyzed using our probe. Thus, the Cy3CS probe offers a significant advancement in the detection of chemical warfare agent’s simulant, with performance metrics that include excellent sensitivity, selectivity, and simplicity of use, establishing it as a promising tool for environmental monitoring and public health safety.