A water-soluble dual-site fluorescent probe for the rapid detection of cysteine with high sensitivity and specificity.

A water-soluble turn-on fluorescent probe has been rationally designed and synthesized to distinguish Cys from Hcy and GSH in less than five seconds. It has high sensitivity and strong anti-interference ability to other amino acids and ions. Its ultra-rapid detection of Cys in aqueous systems could be attributed to dual response sites imparted by the probe.