A selective fluorescence probe for copper(II) ion in aqueous solution based on a 1,8-naphthalimide Schiff base derivative

Abstract

In order to realize real-time monitoring of Cu2+, a new fluorescent probe HL, a Schiff base derivative of N-n-butyl-4-[2]-1,8-naphthalimide, has been designed and synthesized. In methanol-HEPES [2-(4-(2-hydroxyethyl)-1-piperazinyl)-ethanesulfonic acid] solution (1:1, v/v, pH = 7.4) HL showed excellent selectivity towards Cu2+ over other common coexisting metal ions. The fluorescence intensity for HL showed a good linearity with the concentration of Cu2+ ions in the range of 0.5–5.0 μm. Based on combined fluorescence titration, Job’s plot analysis, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry results, Cu2+ forms a 1:2 complex with L. The fluorescence intensity of HL exhibits significant quenching after binding with Cu2+, owing to the strong, intrinsic paramagnetic behavior of Cu2+. Ultimately, in order to test the performance of the synthesized probe, HL was preliminarily applied to the determination of Cu2+ in the Yellow River and in tap water with satisfying results.

Naphthalimide-Piperazine Derivatives as Multifunctional “On” and “Off” Fluorescent Switches for pH, Hg2+ and Cu2+ Ions

“…The detection limit of NI-1 is 1.5 × 10 −8 M and 8.8 × 10 −8 M for Cu 2+ and Hg 2+ ion, respectively. These values are comparable to similar fluorescent quenching chemosensors utilizing the naphthalimide structure with aliphatic amino receptors, reported previously [ 52 , 53 , 54 , 55 ]. Wu et al [ 37 ] determined the limit of detection of Hg 2+ ions by naphthalimide-based optode to be 2.00 × 10 −6 M at pH 7.01 in 0.05 M Tris-HCl which is significantly higher than the detection limit of the compound NI-1 .…”

Construction of Chitosan-Modified Naphthalimide Fluorescence Probe for Selective Detection of Cu2+

“…Different probes derived from chitosan-based naphthalimide or naphthalimide displayed different characteristics, exhibiting fluorescence enhancement or quenching, which demonstrated a quick response [ 27 , 28 , 29 ], potential application value [ 27 , 30 , 31 , 32 ] and high sensitivity [ 27 , 29 , 31 ]. Meanwhile, various drawbacks could not be ignored, such as the organic solvent for dissolving [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ], the long equilibrium time [ 31 , 32 ], narrow detection ranges [ 28 ], and low sensitivity [ 29 , 31 ]. Our probe P was a valuable probe with a fast equilibrium time, wide detection range, good reversibility, a visible light for excitation and emission.…”