An aqueous methylated chromenoquinoline-based fluorescent probe for instantaneous sensing of thiophenol with a red emission and a large Stokes shift

A sensitive and selective fluorescent probe, MCQ-O-DNB, for the detection of thiophenol in aqueous media has been developed based on a methylated chromenoquinoline chromophore. This probe can instantaneously respond to thiophenol and reach to a balance within 2 min. In the detection process, this probe exhibited a large Stokes shift (108 nm) and a low detection limit (8.1 nM, based on S/N = 3). Importantly, practical application experiments demonstrated that this probe was able to detect thiophenol in real water samples and living cells.