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

Abstract

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 (Cd²⁺, Hg²⁺, Cu²⁺, and Pb²⁺). 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-NH₂ composite nanomaterials (UiO-66-NH₂/SPCE). The sensing platform is composed of three-dimensional graphene (3DGO), aminated UiO-66 metal-organic framework, named 3DGO/UiO-66-NH₂. It is worth noting that the porous structure, amino functional groups on the surface, and large specific surface area of UiO-66-NH₂ can enrich and promote the absorption of heavy metal ions. 3DGO was introduced to improve the electrochemical activity and conductivity of UiO-66-NH₂ material. The construction of this new sensing platform, which can synchronously, reliably, and sensitively simultaneously detect Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺ 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.

Keywords: 3DGO; Electrochemical sensing platform; Heavy metal ion; Simultaneous detection; UiO-66-NH2.