Selective and sensitive Detection of Cu2+ in aqueous solution based on cation exchange by Metal−Organic framework TMU-16 as a fluorescent sensor

Recently, metal−organic frameworks (MOFs) have been considered as fluorescence sensors. Herein, we reported the fluorescent TMU-16 for detection of Cu 2+ in aqueous solution with high sensitivity and selectivity. Fluorescence quenching was controlled through the cation exchange mechanism between Cu 2+ and Zn 2+ ions in TMU-16. The strong-fluorescent TMU-16 was converted to a weak-fluorescent TMU-16 (Zn, Cu) and caused highly selective and sensitive detection of Cu 2+ in aqueous medium with a 25–400 ppm linear range and 3.96 ppm limit of detection. No interferences from 200 ppm cation solutions of Hg 2+ , Ag + , Ni 2+ , Pb 2+ , Cr 3+ , Co 2+ , Cd 2+ , and Fe 3+ were observed for the detection of 25 ppm Cu 2+ . The possible mechanism for the quenching effect of Cu 2+ on the fluorescence sensing of TMU-16 was elucidated by inductively coupled-plasma spectrometry (ICP), X-ray diffraction spectrometry (XRD), Fourier transform-infrared spectrometry (FT-IR), Energy-dispersive X-ray spectroscopy (EDX) and elemental mapping techniques. • TMU-16 act as a fluorescent sensor for the detection of Cu 2+ in aqueous solutions. • Quenching fluorescent of TMU-16 in the presence of Cu 2+ was observed. • Cation exchange between Cu 2+ and Zn 2+ is responsible for the fluorescence quenching. • Cu 2+ detection is done selectively in the presence of interfering ions.