Three-dimensional graphene/amino-functionalized metal-organic framework for simultaneous electrochemical detection of Cd(II), Pb(II), Cu(II), and Hg(II).

Trace detection of multiple toxic heavy metals is a very important and difficult problem, conveniently, sensitively, and reliably. In this work, we developed an innovative electrochemical sensor for simultaneously detected heavy metal ions (Cd, Hg, Cu, and Pb). In order to detect trace amounts of Cd(II), Pb(II), Cu(II), and Hg(II) in food quickly, accurately, and at low cost, this study used electrochemical reduction to prepare a screen-printed electrode (3DGO) modified with 3DGO and UiO-66-NH composite nanomaterials (UiO-66-NH/SPCE). The sensing platform is composed of three-dimensional graphene (3DGO), aminated UiO-66 metal-organic framework, named 3DGO/UiO-66-NH. It is worth noting that the porous structure, amino functional groups on the surface, and large specific surface area of UiO-66-NH can enrich and promote the absorption of heavy metal ions. 3DGO was introduced to improve the electrochemical activity and conductivity of UiO-66-NH material. The construction of this new sensing platform, which can synchronously, reliably, and sensitively simultaneously detect Cd, Pb, Cu, and Hg only in 150 s in the linear range of 0.01-0.35 pM with the detection limitations, is 10.90 fM, 5.98 fM, 2.89 fM, and 3.1 fM, respectively. This method provides a new strategy that uses MOF materials for electrochemical detection of a variety of heavy metal ions in food.