Fluorescence spectral detection of copper(II), mercury(II) and zinc(II) based on a multifunctional peptide-based sensor

Abstract

A fluorescence peptide-based sensor (Dansyl-His-Thr-Glu-His-Trp-NH2, D-P5) was synthesized by Fmoc solid phase peptide synthesis, using dansyl group as the fluorophore. The sensor exhibited different fluorescence responses and sensitive detections for copper(II), mercury(II) and zinc(II) ions as a multifunctional sensor. The detailed investigation suggested that the limits of detection were 37.6 nmol⋅L−1, 37.8 nmol⋅L−1 and 59.4 nmol⋅L−1 for copper(II), mercury(II) and zinc(II) ions, respectively, and the highly sensitive sensor was not influenced by other species. The sensor exhibited a strong binding ability to copper(II), mercury(II) and zinc(II) ions with the binding constants of 3.23 × 105 L⋅mol−1, 6.37 × 105 L⋅mol−1 and 6.0 × 104 L⋅mol−1, respectively. The binding stoichiometries of the sensor to copper(II), mercury(II) and zinc(II) ions measured by Job's plot were all 1:1. Furthermore, The sensor has been successfully used for the detections of copper(II), mercury(II) and zinc(II) in actual water samples.