Fluorescent sensor of copper(II) ions based on PMBA microtubes with 4-methoxy-1,8-naphthalimide groups

Abstract

In this article, a high performances hydrophilic tubular fluorescent sensor for Cu(II) detection was fabricated via immobilizing fluorophore 4-methoxy-1,8-naphthalimide groups on poly(N, N′-methylene bisacrylamide) (PMBA) microtubes. The modified polymer microtubes were characterized fully by SEM, FT-IR, EDS mapping, fluorescence microscope and fluorescence spectrometer. This fluorescent sensor displayed high fluorescence emission intensity at 457 nm under irradiation, and exhibited an obvious selective quenching effect in the presence of Cu(II) alone or with a variety of other cations in aqueous solution. Based on the fluorescence intensities before and after quenching, the concentration of Cu(II) could be calculated accurately. Moreover, the fluorescent sensor could be regenerated using ethylene diamine tetraacetic acid (EDTA) as the chelating agent. The regenerated sensor could be reused for many times without performance deteriorate. The mechanism of quenching and regenerating, and the role of the tubes were discussed.