Surface Characterization of New Azulene-Based CMEs for Sensing

Films of 2-(azulen-1-yldiazenyl)-5-phenyl-1,3,4-thiadiazole (T) were successfully deposited on glassy carbon surfaces to prepare chemically modified electrodes (CMEs). Their surface characterization was analyzed by electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). This complexing monomer has been deposited through direct electropolymerization in conditions established during the electrochemical characterization of T performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and rotating disk electrode voltammetry (RDE). These methods put in evidence the high degree of asymmetry of oxidation and reduction curves, which is due to the irreversible processes occurring at opposite potentials. The film formation was confirmed by ferrocene redox assay probe. The properties of the electrodes modified with T (T-CMEs) were investigated for sensing heavy metal (HM) ions in water solutions, with promising results for Pb(II) among Cd(II), Cu(II), and Hg(II) ions.

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The Heavy Metals Sensing Based on 2,6-Bis(-2-(Thiophen-3-yl)Vinyl)-4-(4,6,8-Trimethylazulen-1-yl)Pyrylium Modified Electrodes

Revista de Chimie ◽

10.37358/rc.17.11.5917 ◽

2017 ◽

Vol 68 (11) ◽

pp. 2509-2513

Author(s):

Ioana Georgiana Lazar ◽

Elena Diacu ◽

George Octavian Buica ◽

Eleonora Mihaela Ungureanu ◽

Georgiana Luiza Arnold ◽

...

Keyword(s):

Heavy Metal Ions ◽

Modified Electrodes ◽

Rotating Disk ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Controlled Potential Electrolysis ◽

Rotating Disk Electrode Voltammetry ◽

Controlled Potential ◽

Pulse Voltammetry

This paper focuses on electrochemical characterization of new azulene compound 2,6-bis((E)-2-(thiophen-3-yl)vinyl)-4-(4,6,8-trimethylazulen-1-yl)pyrylium (L) by cyclic voltammetry (CV), differential pulse voltammetry (DPV), rotating disk electrode voltammetry (RDE) on glassy carbon disk working electrodes. The character of redox processes was established by CV and RDE using increasing scan rates at different scan domains. PolyL modified electrodes have been prepared by scanning or controlled potential electrolysis (CPE). The complexing properties of L and polyL have been investigated towards detection of heavy metal ions by anodic stripping technique. The voltammetric curves present well defined peaks for Pb2+, Cd2+, Cu2+ and Hg2+, which can be used as analytical signals for their determination. The performances of the modified electrodes obtained at different potentials and charges have been evaluated. The best results have been obtained for Pb2+ and Cd2+ with the achievement of detection limits of 10-7 M.

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Recognition of Heavy Metal Ions by Using E-5-((5-Isopropyl-3,8-Dimethylazulen-1-yl) Dyazenyl)-1H-Tetrazole Modified Electrodes

Symmetry ◽

10.3390/sym13040644 ◽

2021 ◽

Vol 13 (4) ◽

pp. 644

Author(s):

Adina-Maria Păun ◽

Ovidiu-Teodor Matica ◽

Veronica Anăstăsoaie ◽

Laura-Bianca Enache ◽

Elena Diacu ◽

...

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Heavy Metal Ions ◽

Film Formation ◽

Modified Electrodes ◽

Rotating Disk ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Polymeric Films ◽

Rotating Disk Electrode Voltammetry

Chemically modified electrodes (CMEs) based on polymeric films of E-5-((5-isopropyl-3,8-dimethylazulen-1-yl) diazenyl)-1H-tetrazole (L) deposited on the surface of the glassy carbon electrode have been used for the recognition of heavy metal (Me) ions. The electrochemical study of L was done by three methods: differential pulse voltammetry (DPV), cyclic voltammetry (CV), and rotating disk electrode voltammetry (RDE). The CV, DPV, and RDE studies for L were performed at different concentrations in 0.1 M tetrabutylammonium perchlorate solutions in acetonitrile. The polymeric films were formed by successive cycling or by controlled potential electrolysis (CPE). The film formation was proven by recording the CV curves of the CMEs in ferrocene solution. The CMEs prepared at different charges or potentials were used for detection of heavy metal ions. Synthetic samples of heavy metal ions (Cd(II), Pb(II), Cu(II), Hg(II)) of concentrations between 10−8 and 10−4 M were analyzed. The most intense signal was obtained for Pb(II) ion (detection limit of about 10−8 M). Pb(II) ion can be detected by these CMEs in waters at such concentrations. The ability of the ligand L to form complexes with Pb(II) and Hg(II) ions was also tested by UV-Vis spectrometry. The obtained results showed the formation of Me(II)L2 complexes.

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Polyazulenes Based Materials for Heavy Metal Ions Detection

Revista de Chimie ◽

10.37358/rc.17.10.5858 ◽

2017 ◽

Vol 68 (10) ◽

pp. 2215-2218

Author(s):

Alexandra Oprisanu ◽

Ioana Georgiana Lazar ◽

Maria Daniela Pop ◽

Eleonora Mihaela Ungureanu ◽

Raluca Isopescu ◽

...

Keyword(s):

Cyclic Voltammetry ◽

Electrochemical Polymerization ◽

Modified Electrodes ◽

Functional Materials ◽

Rotating Disk ◽

Differential Pulse ◽

Membered Ring ◽

Rotating Disk Electrode ◽

Rotating Disk Electrode Voltammetry ◽

Metal Ions Detection

Azulene is a special monomer used to functionalize electrodes due to its high polarizability, because it makes possible spontaneous electron drift from the five-membered ring to the seven-membered ring. Our study concerns the electrochemical characterization by cyclic voltammetry, differential pulse-voltammetry and rotating disk electrode voltammetry of a new azulene monomer, 4-(5-isopropyl-3,8-dimethylazulen-1-yl)-2,6-bis((E)-2-(thiophen-2-yl)vinyl) pyridine (L). It has been used to obtain complexing modified electrodes by electrochemical polymerization. PolyL films modified electrodes have been characterized by cyclic voltammetry in ferrocene probe solution. The complexing properties of polyL based functional materials have been investigated towards heavy metals (Pb, Cd Hg, Cu) by preconcentration � anodic stripping technique.

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Electrochemical Characterization of Some Pyrrolo[1,2-c]Pyrimidine Derivatives

Revista de Chimie ◽

10.37358/rc.18.2.6135 ◽

2018 ◽

Vol 69 (2) ◽

pp. 499-506 ◽

Cited By ~ 2

Author(s):

Marian Laurentiu Tatu ◽

Florian Harja ◽

Eleonora Mihaela Ungureanu ◽

Emilian Georgescu ◽

Marcel Mirel Popa

Keyword(s):

Modified Electrodes ◽

Rotating Disk ◽

Differential Pulse ◽

Electrochemical Characterization ◽

Rotating Disk Electrode ◽

Pyrimidine Derivatives ◽

Controlled Potential Electrolysis ◽

Controlled Potential ◽

Voltammetric Methods

The electrochemical characterization of two pyrrolo[1,2-c]pyrimidine derivatives (I1 and I2) was realized by cyclic, differential pulse, and rotating disk electrode voltammetric methods. The character of redox processes was established by scanning on different domains and with different scan rates. The diffusion coefficients were determined. Modified electrodes have been obtained by cycling the potential or by controlled potential electrolysis at anodic potentials. The electrodes obtained with polyol1 and polyI2 films were characterized by cyclic voltammetry in ferrocene solution.

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New Azulene Modified Electrodes for Heavy Metal Sensing

Revista de Chimie ◽

10.37358/rc.17.9.5850 ◽

2017 ◽

Vol 68 (9) ◽

pp. 2172-2175

Author(s):

Maria Daniela Pop ◽

Veronica Anastasoaie ◽

Mariana Apostoiu Popescu ◽

Alexandra Oprisanu ◽

Eleonora Mihaela Ungureanu ◽

...

Keyword(s):

Modified Electrodes ◽

Rotating Disk ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Controlled Potential Electrolysis ◽

Controlled Potential ◽

Pulse Voltammetry ◽

Heavy Metal Sensing ◽

Metal Sensing

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.

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Electroactive properties of a new azulene thioxo-imidazolidin-4-one ligand for modified electrodes

Journal of Electrochemical Science and Engineering ◽

10.5599/jese.727 ◽

2020 ◽

Vol 10 (2) ◽

pp. 209-217

Author(s):

Elena Diacu ◽

Adinuta Paun ◽

Veronica Anastasoaie ◽

Georgiana-Luiza Arnold-Tatu ◽

Liviu Birzan ◽

...

Keyword(s):

Modified Electrodes ◽

Rotating Disk ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Electrode Potentials ◽

Controlled Potential Electrolysis ◽

Analytical Response ◽

Controlled Potential ◽

Cadmium Lead

The electrochemical characterization of a new synthesized azulene compound (Z)-5-((5-isopropyl-3,8-dimethylazulen-1-yl)methylene)-2-thioxoimidazolidin-4-one (L) using cyclic voltammetry, differential pulse voltammetry and rotating disk electrode is presented. Chemically modified electrodes were obtained by successive scanning or by controlled potential electrolysis using different electrode potentials or charges. The new modified electrodes were tested in solutions containing different concentrations of the following heavy metals: cadmium, lead, mercury and copper. A good analytical response was obtained for Pb2+.

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Chemically Modified Electrodes Based on 4-(azulen-1-yl)-2,6-bis ((e)-2-(thiophen-2-yl)vinyl) Pyrylium Perchlorate

Revista de Chimie ◽

10.37358/rc.20.9.8322 ◽

2020 ◽

Vol 71 (9) ◽

pp. 113-124

Author(s):

Ioana-Georgiana Bugean ◽

Adinuta Paun ◽

Elena Diacu ◽

Mihaela Cristea ◽

Liviu Birzan ◽

...

Keyword(s):

Electrochemical Polymerization ◽

Modified Electrodes ◽

Rotating Disk ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Chemically Modified ◽

Controlled Potential Electrolysis ◽

Rotating Disk Electrode Voltammetry ◽

Controlled Potential ◽

Heavy Metals Ions

The electrochemical behavior of 4-(azulen-1-yl)-2,6-bis((E)-2-(thiophen-2-yl)vinyl) pyrylium perchlorate (L) was studied by cyclic voltammetry, differential pulse voltammetry, and rotating disk electrode voltammetry. The electrochemical polymerization of L was studied. Modified electrodes covered by polyL films were obtained by successive scanning or by controlled potential electrolysis (CPE) at different charges and potentials. The new electrodes obtained by CPE were applied for sensing the following heavy metals ions: Cu(II), Pb(II), Cd(II), Hg(II). The best results have been registered for Pb(II) ion with a detection limit of 10-8 M.

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Electrochemistry in Nanostructered Inorganic Molecular Materials

MRS Proceedings ◽

10.1557/proc-676-y1.5 ◽

2001 ◽

Vol 676 ◽

Cited By ~ 1

Author(s):

Mary Elizabeth Williams ◽

Joseph T. Hupp

Keyword(s):

Electrochemical Techniques ◽

Rotating Disk ◽

Rotating Disk Electrode ◽

Primary Methods ◽

Bridging Ligands ◽

Sensing Applications ◽

Rotating Disk Electrode Voltammetry ◽

Molecular Squares ◽

Electrochemical Microscopy

ABSTRACTWe have previously described the synthesis of a family of molecular ‘squares’ based on octahedral Re(I) coordination of difunctional bridging ligands. The size and chemical composition of the square cavity is highly tunable, and the inorganic cyclophanes are being actively studied in catalytic, separations, and sensing applications. Electrochemical techniques have been primary methods for characterization of the transport properties of thin films of the nanostructured materials. For example, cyclic voltammetry and rotating disk electrode voltammetry experiments have revealed size-selective permeation by redox probes, where the size cutoff is determined by the internal square dimensions. We have more recently begun to employ scanning electrochemical microscopy to spatially image micropatterned electrodes containing these thin film materials, simultaneously allowing us to obtain permeability data and topographical information. This paper describes data obtained by employing porphyrin-based molecular squares that feature chemically tailored cavities.

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Polyazulene-Based Materials for Heavy Metal Ion Detection. 3. (E)-5-((6-t-Butyl-4,8-dimethylazulen-1-yl) diazenyl)-1H-tetrazole-Based Modified Electrodes

Symmetry ◽

10.3390/sym13091642 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1642

Author(s):

Laura-Bianca Enache ◽

Veronica Anăstăsoaie ◽

Cecilia Lete ◽

Alina Giorgiana Brotea ◽

Ovidiu-Teodor Matica ◽

...

Keyword(s):

Heavy Metal ◽

Metal Ion ◽

Electrochemical Sensors ◽

Electrochemical Impedance ◽

Electrochemical Techniques ◽

Free Ligand ◽

Modified Electrodes ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Ion Detection

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).

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Electrochemical Comparison on New (Z)-5-(Azulen-1-Ylmethylene)-2-Thioxo-Thiazolidin-4-Ones

Symmetry ◽

10.3390/sym13040588 ◽

2021 ◽

Vol 13 (4) ◽

pp. 588

Author(s):

Eleonora-Mihaela Ungureanu ◽

Mariana Popescu (Apostoiu) ◽

Georgiana-Luiza Tatu (Arnold) ◽

Liviu Birzan ◽

Raluca Isopescu ◽

...

Keyword(s):

Oxidation Mechanism ◽

Stripping Voltammetry ◽

Rotating Disk ◽

Differential Pulse ◽

Rotating Disk Electrode ◽

Carbon Electrodes ◽

Glassy Carbon Electrodes ◽

Alkyl Groups ◽

Rotating Disk Electrode Voltammetry ◽

Pulse Voltammetry

Three (Z)-5-(azulen-1-ylmethylene)-2-thioxo-thiazolidin-4-ones are electrochemically characterized by cyclic voltammetry, differential pulse voltammetry, and rotating disk electrode voltammetry. The electrochemical investigations revealed that the redox potential is influenced by the number and position of the alkyl groups, and the possible oxidation mechanism is proposed. These compounds, after their immobilization on glassy carbon electrodes during oxidative electropolymerization, were examined as complexing ligands for heavy metal ions from aqueous solutions through adsorptive stripping voltammetry.

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