New Azulene Modified Electrodes for Heavy Metal Sensing

Abstract

The electrochemical characterization of 2,6-bis((E)-2-(furan-2-yl)vinyl)-4-(5-isopropyl-3,8-dimethylazulen-1-yl) pyridine has been performed by cyclic voltammetry, differential pulse voltammetry and rotating disk electrode. Modified electrodes were obtained by cycling the potential in the anodic scans or by controlled potential electrolysis (CPE) at different potentials and charges. The modified electrodes have been tested for mercury, cadmium, copper and lead ions detection.

Polyazulene-Based Materials for Heavy Metal Ion Detection. 2. (E)-5-(azulen-1-yldiazenyl)-1H-Tetrazole-Modified Electrodes for Heavy Metal Sensing

“…Open-circuit chemical preconcentration coupled with the anodic stripping technique has been applied for this purpose in a similar manner by other studies [10,12]. Those studies worked towards obtaining sensors for heavy metals with the highest possible performances using new materials-alternatives to the existing ones (having another monomer besides pyrrole and aniline or thiophene)-and the expertise of researchers in azulene synthesis [10][11][12][13][14][15], in electrochemical characterization of small molecules [10,11,14,15] in obtaining and characterizing modified electrodes based on azulene [10][11][12][13][14][15][16][17] and in the use of sensors for dosing heavy metals (with good results, especially for lead) [18][19][20]. The present paper proposes the use of an azulene derivative having azotetrazole as a strong attractant of metal ions, in order to create a sensor for heavy metals.…”

Properties Assessment by Quantum Mechanical Calculations for Azulenes Substituted with Thiophen– or Furan–Vinyl–Pyridine

“…These modified electrodes were used for HMs recognition through preconcentration and anodic stripping. A good result has been observed for Pb (detection limit of 10 −7 M) [4]. The electrochemical study of ligand established the best conditions for obtaining CMEs, which were tested for the recognition of HMs cations with good results for lead and for copper at concentrations lower than 10 −8 M [3].…”

“…These values are listed in Table 3 for oxygen and sulfur derivatives. The data were collected in 0.5 mM solutions of each ligand in 0.1 M tetrabutylammonium perchlorate in acetonitrile [3][4][5]21,22]. The calculated HOMO and LUMO energies (Table 1) were plotted against experimental oxidation and reduction potentials.…”

“…Chemically modified electrodes (CMEs) obtained by electrochemical polymerization of differently substituted azulene monomers have been previously tested and characterized by electrochemistry [1,2]. The previously reported data refer to heavy metals (HMs) ions recognition attempts to detect very low concentrations of contaminants such as cadmium, copper, mercury, chromium, cobalt, nickel, or lead in water [3][4][5]. The advantage is certain in the context of health concerns due to the harmful effects of these HMs on humans; their bioaccumulation in the human body causes acute or chronic toxicity, responsible for serious disorders especially at long-term exposure.…”