Polyazulene-Based Materials for Heavy Metal Ion Detection. 3. (E)-5-((6-<i>t</i>-Butyl-4,8-dimethylazulen-1-yl) diazenyl)-1H-tetrazole-Based Modified Electrodes
Laura-Bianca Enache,
Veronica Anăstăsoaie,
Cecilia Lete,
Alina Giorgiana Brotea,
Ovidiu-Teodor Matica,
Cristina-Andreea Amarandei,
Jérémy Brandel,
Eleonora-Mihaela Ungureanu,
Marius Enăchescu
Affiliations
Laura-Bianca Enache
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University “Politehnica” of Bucharest, Gheorghe Polizu 1-7, Sector 1, 011061 Bucharest, Romania
Veronica Anăstăsoaie
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University “Politehnica” of Bucharest, Gheorghe Polizu 1-7, Sector 1, 011061 Bucharest, Romania
Cecilia Lete
Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest, Romania
Alina Giorgiana Brotea
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University “Politehnica” of Bucharest, Gheorghe Polizu 1-7, Sector 1, 011061 Bucharest, Romania
Ovidiu-Teodor Matica
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University “Politehnica” of Bucharest, Gheorghe Polizu 1-7, Sector 1, 011061 Bucharest, Romania
Cristina-Andreea Amarandei
Hubert Curien Pluridisciplinary Institute (IPHC), Université de Strasbourg/CNRS (UMR7178), 23 rue du Loess, 67087 Strasbourg, France
Jérémy Brandel
Hubert Curien Pluridisciplinary Institute (IPHC), Université de Strasbourg/CNRS (UMR7178), 23 rue du Loess, 67087 Strasbourg, France
Eleonora-Mihaela Ungureanu
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University “Politehnica” of Bucharest, Gheorghe Polizu 1-7, Sector 1, 011061 Bucharest, Romania
Marius Enăchescu
Center for Surface Science and Nanotechnology, University “Politehnica” of Bucharest, Splaiul Independentei 313, 060042 Bucharest, Romania
A recently synthesized azulene-tetrazole molecular receptor is proposed in this paper to continue the series of azulene substituted compounds that have been developed to build polyazulene-based materials for heavy metal (HM) ion detection. This study focuses on characterization of (E)-5-((6-t-butyl-4,8-dimethylazulen-1-yl) diazenyl)-1H-tetrazole (L) by electrochemical techniques in view of its use for designing electrochemical sensors for HM ion complexation. The character of redox processes was proved by cyclic, differential pulse, and rotating disk electrode voltammetry. An in-depth thermodynamic study of the complexation properties of the free ligand with Pb(II) and Cd(II) from aqueous solutions was performed, and the stoichiometry and stability constant values were determined. Chemically modified electrodes (CMEs) based on L (L-CMEs) prepared by controlled potential electrolysis (CPE) at different applied potentials and charges were characterized by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Their surface morphology was examined by scanning electron microscopy (SEM). The complexing properties of L-CMEs were investigated towards the detection of HM ions by anodic stripping and compared to the stability constants of the complexes in solution. Voltametric curves showed well-defined peaks for Pb (II), Cd (II), Cu (II) and Hg (II), but the responses differ from each other and vary depending on the ion concentrations in the accumulation solutions. The best results were obtained for Pb(II) and Cd(II) ions. The results obtained for Pb(II) are promising and can be used for its analysis in water solutions (detection limit of about 10−9 M).
