A selective turn-on fluorescent sensor for sulfur mustard simulants.

A fluorescent turn-on sensor for the selective and sensitive detection of sulfur mustard simulants in water that uses a metal-ion indicator displacement assay (IDA) has been devised. In this IDA approach, a sulfur mustard simulant (the analyte) is allowed to react with a dithiol (1) to form a podand (2). This podand has a strong affinity to bind with Cd(2+) and displaces an indicator (4-methylesculetin, ME) from a Cd(2+)-indicator complex (8) to give a turn-on of fluorescence. The detection is rapid and highly selective, as we did not observe any interference from other electrophiles, even from the oxygen analogue of the mustard simulant. The protocol was successfully used for the detection of the simulant present on surfaces and in soil samples.