A Novel Camphor-Based “Turn-on” Fluorescent Probe with High Specificity and Sensitivity for Sensing Mercury(II) in Aqueous Medium and Its Bioimaging Application

Precise detection of Hg 2+ in an ecological environment and biological system is of great importance. Hence, in this paper, we have constructed a simple fluorescent turn-on probe CP-Hg toward Hg 2+ based on natural and renewable camphor. A significantly enhanced green fluorescence was clearly observed only with the participation of Hg 2+ due to the Hg 2+ -mediated deprotection reaction of thioacetal. The probe CP-Hg could also sensitively detect Hg 2+ with a detection limit of 19.3 nM and a large Stokes shift of 153 nm in a near-perfect aqueous solution. The reaction mechanism was fully analyzed through 1 H NMR (proton nuclear magnetic resonance), ESI-MS (electrospray ionization mass spectrometry), and DFT (density functional theory) calculations. Moreover, the CP-Hg-coated test strips were successfully fabricated for naked-eye detection of Hg 2+ . Furthermore, the cell imaging experiment manifested that the probe CP-Hg is suitable for labeling intracellular Hg 2+ .