C2-Symmetric Benzene-Based Hydrogel Modified Electrode for the Determination of Copper Ion by Stripping Voltammetry

Abstract

In the last few years, low molecular organogels (LMWG) have attracted much interest due to their unique properties, including high adsorption capacity, high specific surface area, high porosity and rich functional groups binding with other guest species. LMWG based materials have wide applications in various field, such as separation technologies, tissue engineering, sensors, catalysis [1-4]. LMWGs are usually obtained by self-assembly of low molecular(typically with a molecular weight < 1000 Da)weight gelators in organic solvents or in water, to form fibrous structure through non-covalent interactions such as hydrogen bonding, π-π stacking, metal coordination, coulomb forces, and van der Waals interactions[5] .C2-symmetric benzene-based hydrogel (C2-BHG) is a new type of LMWGs with a 1,4-dimine benzene as the symmetric structure which can provide strong parallel interactions between hydrogen-bonding amide moieties. The C2-BHG has been used as an adsorbent to remove the toxic materials due to its strong adsorption ability [5]. The C2-BNG can self-assemble on many surfaces to form fibrous network structure through the π–π stacking between the adjacent phenyl groups or hydrogen bonding.In this report, the C2-BHG modified glassy carbon electrode (C2-BHG/GCE) was fabricated by self assembly at a suitable assembly temperature. The gelation and self-assembly of C2-GHB can occur simultaneously on the carbon surface with a uniform film thickness. The film properties were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of redox probes. The morphology of C2-GHB-modified layer was characterized by atomic force microscopy (AFM). The porous membrane structure with a high surface area could provide rich active sites to interact with the target substance. In addition, the C2-GHB-modified layer contains a large amount of hydroxyl group on the hydrophilic chain. The sensing properties of the C2-BHG/GCE to Cu(II) ions were investigated with sensitive response. Under the optimized conditions (such as preconcentration time, preconcentration potential and electrolyte type), the linear range of Cu(II) ions was determined between 1ppt-800ppt and 1ppb-100ppb, with a detection limit down to 0.5 ppt. The complex interaction of C2-BHG with Cu2+ was confirmed by UV-Vis characterization.As a new kind of low molecular organogel modifier, C2-GHB is a promising material in the development of a new type of chemical modified electrode for sensor application.