Facile one-pot synthesis of triethanolamine-functionalized AuNPs-GO-UiO-66-NH 2 nanocomposites for simultaneous electrochemical detection of Cd(II), Pb(II), and Cu(II)

This work provides a facile electrochemical method for simultaneous detection of Cd 2+ , Pb 2+ , and Cu 2+ , on the base of one-pot synthesis of triethanolamine (TEOA)-functionalized gold nanoparticle (AuNP)-metal–organic framework-graphene oxide nanocomposites (TEOA@AuNPs-GO-UiO-66-NH 2 ). In this method, TEOA not only can act as a base for the deprotonation of 2-aminoterephthalic acid, leading to in situ synthesizing the UiO-66-NH 2 on the GO nanosheets by a one-step hydrothermal method, but also can be used as a reductant reacted with HAuCl 4 to form AuNPs, improving the conductivity of the composite by accelerating the electron transfer. Moreover, this composite can serve as an enrichment medium phase of heavy metal ions because of the interaction between metal cations and hydrophilic groups of TEOA, UiO-66-NH 2 , or GO, which have the synergic effect of enhancing the electrochemical signals. The morphology and structure information of TEOA@AuNPs-GO-UiO-66-NH 2 composite were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FT-IR). Under the optimal conditions, the TEOA@AuNPs-GO-UiO-66-NH 2 -modified electrode was applied for individual and simultaneous electrochemical detection for the Cd 2+ , Pb 2+ , and Cu 2+ in an acetic acid buffer solution with satisfactory linear range and significantly low limits of detection. This electrochemical sensor was successfully utilized for simultaneous detection of Cd 2+ , Pb 2+ , and Cu 2+ in river water with great selectivity and accuracy, displaying great potential application in food safety and environmental monitoring. Graphical abstract