Highly selective fluorescence turn-on chemosensor based on naphthalimide derivatives for detection of copper(II) ions

A new fluorescent probe, DN-SB, was synthesized. DN-SB was based on the naphthalimide derivatives and exhibited high selectivity and sensitivity for Cu2+ ions. As a Cu2+-amplified fluorescent probe, its fluorescence spectrum showed 4.5-fold enhancement in the intensity of the signal at 519 nm on binding with the Cu2+. Based on the fluorescence titration spectra and job’s-plot, binding mode of DN-SB with Cu2+ was proposed. Fluorescence intensity was linear with concentration of Cu2+ cation in a range from 4 μM to 7 μM. DN-SB was also sensitive for copper ions. The detection limit was calculated to be 0.15 μM which indicated DN-SB was sensitive to Cu2+.

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► It was a turn-on sensor for copper(II) ions based on naphthalimide derivatives.
► It had a good selectivity for copper(II) ions.
► The sensor had a low detection limit (0.15 μM).