Highly sensitive detection of Pb and Cu based on ZIF-67/MWCNT/Nafion-modified glassy carbon electrode.

A series of different facile modification layers (MLs) was designed to gradually increase the electrochemical sensing performance of glassy carbon electrode (GCE) for simultaneously detecting Pb and Cu. ML designs were mainly a different combination of ZIF-67, MWCNT and Nafion, and their different electrochemical sensing performances were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), square wave stripping voltammetry (SWSV) and chronocoulometry. The fabricated sensor, which modified with ZIF-67/MWCNT and Nafion layer, exhibited the biggest response peak current to Pb and Cu. In addition, it displayed a wide linear detection range of 1.38 nM-5 μM for Pb and 1.26 nM-5 μM for Cu, a detection accuracy of about 1 nM for both Pb and Cu, and an excellent stability for both Pb and Cu. We also analyzed the real water sample taken from Changchun's Sanjia Lake and Yan Lake. We believe this ML design provides instruction for building high-performance electrochemical sensing systems.