Ag metal organic frameworks nanocomposite modified electrode for simultaneous electrochemical detection of copper (II) and lead (II)

The detection of biologically important metal ions such as Cu(II) and Pb(II) ions using an electrochemical approach at sensitive level is gaining great attention to reveal the health conditions of patients with serious diseases such as rickets, bone deterioration, and heart disease that are associated with these metal ions as well as environmental hazards. Thus, rapid and efficient detection methods for these metal ions are in great demand. In this study, we developed an ideal protocol using silver metal–organic framework (Ag@MOF) nanoparticles for the detection of Cu(II) and Pb(II) metal ions. Ag@MOF was synthesized by a reflux method, and the working electrode was prepared by coating Ag@MOF onto ITO glass. Compared with the bare ITO electrode, the Ag@MOF/ITO working electrode exhibited a more sensitive electrochemical performance for the detection of Cu(II) and Pb(II) metal ions through the complexation between the inner core hydroxyl groups of Ag@MOF and the metal ions. The crystallographic and structural analyses of Ag@MOF were carried out by X-ray diffraction analysis and Fourier transform infrared spectroscopy, while morphological analysis was performed by high-resolution transmission electron microscopy and field-emission scanning electron microscopy. X-ray photoelectron spectroscopy was performed to investigate the surface electronic states of silver in Ag@MOF. The cyclic voltammetry results showed that Cu(II) and Pb(II) metal ions can be detected using the Ag@MOF working electrode, which exhibited a more sensitive performance compared with the bare ITO working electrode. Our study shows that the developed electrochemical sensor is ideal for the detection of various metal ions.