A novel fluorescence “on-off-on” peptide-based chemosensor for simultaneous detection of Cu2+, Ag+ and S2−

Abstract A novel peptide fluorescent chemosensor L (FITC-Ahx-GCA-NH 2 ) has been designed and synthesized by solid phase peptide synthesis with Fmoc chemistry which can simultaneously detect Cu 2+ , Ag + and S 2− ions in aqueous solution and living cells. Both Cu 2+ and Ag + non-competitively quench the fluorescence of L at an excitation wavelength of 490 nm. The S 2− anion can restore the quenched fluorescence at 520 nm, completing the fluorescent "on-off-on" cycle. Moreover, L displayed high selectivity and sensitivity for Cu 2+ , Ag + and S 2− . The detection limits for Cu 2+ and S 2− with the L -Cu system were 37 nM and 15 nM, respectively, and for Ag + and S 2− in the L -Ag system the detection limits were 13 nM and 70 nM, respectively. Results of this study suggest that L can be used as a highly selective and sensitive peptide-based fluorescent chemosensor for simultaneous detection of Cu 2+ , Ag + and S 2− ions in both environmental and biological systems.