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Advanced Electrochemical Methods in Molecular Detection

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: 31 August 2024 | Viewed by 4774

Special Issue Editors

Department of Chemistry, State University of Londrina, Londrina, Brazil
Interests: electroanalysis; working electrode materials; photoelectrochemical sensors; synthesis of nanomaterials; pharmaceutical, food, environmental and bio-analysis
Department of Chemistry, State University of Londrina, Londrina, Brazil
Interests: sample preparation; HPLC; atomic absorption spectrometry; electroanalysis; separation science; microextraction techniques; liquid–liquid microextraction; synthesis of nanomaterials; molecularly imprinted polymers; food analysis; environmental analysis; bio-analysis
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Special Issue Information

Dear Colleagues,

Electrochemical techniques have been extensively employed in the electroanalysis of organic and inorganic compounds. They are precise, exact, sensitive, low-cost and require short analysis times. The success of these techniques mainly results from innovations in electrochemical instrumentation, which arose from the development of modern electronic components that enable the use of techniques that involve potential pulses. Techniques such as square wave voltammetry, differential pulse voltammetry and amperometry lead to results with high sensitivity, enabling analyses of water, soil, food and even compounds of biological interest in blood, plasma and urine samples. Furthermore, potentiostats/galvanostats make “in loco” analyses possible. When optimizing an electroanalytical method to determine a particular molecule, it is necessary to consider not only the electrochemical technique but also the materials used in the working electrode. The combination of specially designed sensing interfaces with electrochemical techniques has great potential in enabling more sensitive and selective analytical detection of molecules. In this sense, the advances in biosensors and chemically modified electrodes have increasingly contributed to the development of novel electroanalytical methods. Biosensors based on enzymes, antibodies, aptamers and microbes have been widely used in the development of electroanalytical methods with highly improved performance. For sensor modification, a wide variety of materials can be used, including carbon-based nanomaterials such as carbon nanotubes, black carbon and graphene; chemically imprinted polymers; metallic nanoparticles; hybrid materials; metallic quantum dots; carbon quantum dots; magnetic particles; and metal–organic frameworks.

Given the importance of this topic in electroanalysis, this Special Issue aims to collect original research articles, reviews and technical notes on new advanced electroanalytical methodologies for the determination of organic and inorganic molecules in different samples using different electrochemical sensors. We also welcome papers on the use of new methodologies based on biosensors; chemically modified electrodes; bare electrodes with outstanding performance, such as boron-doped diamond electrodes; and miniaturized, microfluidic and flow systems.

Prof. Dr. Roberta Antigo Medeiros
Prof. Dr. César Ricardo Teixeira Tarley
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • electroanalysis of organic and inorganic molecules
  • electrochemical techniques
  • new electroanalytical methodologies
  • electrochemical sensors
  • electroactive materials
  • biosensors

Published Papers (5 papers)

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Research

12 pages, 2745 KiB  
Article
Application of Potentiometric and Electrophoretic Measurements to Evaluate the Reversibility of Adsorption of Divalent Ions from a Solution on Titanium Dioxide
by Wojciech Piasecki and Karolina Lament
Molecules 2024, 29(3), 555; https://doi.org/10.3390/molecules29030555 - 23 Jan 2024
Viewed by 538
Abstract
The adsorption of divalent ions on metal oxides is controlled by the pH of a solution. It is commonly assumed that this is a reversible process for pH changes. However, there are reports that the sorption of ions on oxides may not be [...] Read more.
The adsorption of divalent ions on metal oxides is controlled by the pH of a solution. It is commonly assumed that this is a reversible process for pH changes. However, there are reports that the sorption of ions on oxides may not be reversible. To verify this, we used potentiometric titration, ion-selective electrodes (ISEs), and electrokinetic measurements to examine the reversibility of the adsorption of hydrogen ions and three metal ions (Ca2+, Cu2+, and Fe2+) on TiO2. The ferrous ion was used as a reference because its adsorption is entirely irreversible. The surface charge determined by potentiometric titration and the adsorption edges measured using ISE indicate that the adsorption of copper ions is reversible with changes in pH. In the case of calcium ions, the results suggest a certain degree of irreversibility. There are apparent differences in the electrokinetic potential data obtained during titration with base and acid, which suggests that the adsorption is irreversible. We have explained this contradiction by considering the complex and dynamic nature of electrophoretic mobility. In our opinion, potentiometric titration may be the simplest and most reliable method for assessing the reversibility of multivalent ion adsorption. Full article
(This article belongs to the Special Issue Advanced Electrochemical Methods in Molecular Detection)
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19 pages, 16294 KiB  
Article
Electrochemical Sensor for Tryptophan Determination Based on Trimetallic-CuZnCo-Nanoparticle-Modified Electrodes
by Adina Arvinte, Ana-Lacramioara Lungoci, Adina Coroaba and Mariana Pinteala
Molecules 2024, 29(1), 28; https://doi.org/10.3390/molecules29010028 - 20 Dec 2023
Viewed by 550
Abstract
The superior properties of electrodeposited trimetallic CuZnCo nanoparticles, arising from the synergistic effect of combining the unique features of metallic components, were confirmed using voltametric measurements. The surface morphology and structure of the as-prepared electrocatalysts were determined using scanning electron microscopy, energy-dispersive X-ray, [...] Read more.
The superior properties of electrodeposited trimetallic CuZnCo nanoparticles, arising from the synergistic effect of combining the unique features of metallic components, were confirmed using voltametric measurements. The surface morphology and structure of the as-prepared electrocatalysts were determined using scanning electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy techniques. Here, the trimetallic CuZnCo nanoparticles were synthesized as a powerful redox probe and highly efficient signal amplifier for the electrochemical oxidation of tryptophan. Differential pulse voltammetry studies showed a linear relationship with a tryptophan concentration of 5–230 μM, and the low detection limit was identified at 1.1 μM with a sensitivity of 0.1831 μA μM−1 cm−2. Full article
(This article belongs to the Special Issue Advanced Electrochemical Methods in Molecular Detection)
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15 pages, 2912 KiB  
Article
Electrochemical Determination of 17-β-Estradiol Using a Glassy Carbon Electrode Modified with α-Fe2O3 Nanoparticles Supported on Carbon Nanotubes
by Juliana Costa Rolim Galvão, Mayara da Silva Araujo, Maiyara Carolyne Prete, Vanildo Leão Neto, Luiz Henrique Dall’Antonia, Roberto Matos, Cesar Ricardo Texeira Tarley and Roberta Antigo Medeiros
Molecules 2023, 28(17), 6372; https://doi.org/10.3390/molecules28176372 - 31 Aug 2023
Cited by 3 | Viewed by 1051
Abstract
In this study, a novel electrochemical assay for determining 17-β-estradiol (E2) was proposed. The approach involves modifying a glassy carbon electrode (GCE) with a nanocomposite consisting of α-Fe2O3 nanoparticles supported on carbon nanotubes (CNTs)—denoted as α-Fe2O3-CNT/GCE. [...] Read more.
In this study, a novel electrochemical assay for determining 17-β-estradiol (E2) was proposed. The approach involves modifying a glassy carbon electrode (GCE) with a nanocomposite consisting of α-Fe2O3 nanoparticles supported on carbon nanotubes (CNTs)—denoted as α-Fe2O3-CNT/GCE. The synthesis of the α-Fe2O3-CNT nanocomposite was achieved through a simple and cost-effective hydrothermal process. Morphological and chemical characterization were conducted using scanning electron microscopy (SEM), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDX). The presence of the α-Fe2O3-CNT film on the GCE surface resulted in an enhanced electrochemical response to E2, preventing electrode surface fouling and mitigating the decrease in peak current intensity during E2 oxidation. These outcomes substantiate the rationale behind the GCE modification. After the optimization of experimental conditions, E2 was determined by the square wave voltammetry technique using 0.1 mol L−1 KCl solution (pH = 7.0) with 20% ethanol as a supporting electrolyte. A linear concentration range of 5.0–100.0 nmol L−1 and a low limit of detection of 4.4 nmol L−1 were obtained. The electroanalytical method using α-Fe2O3-CNT/GCE was applied for E2 determination in pharmaceutical, lake water, and synthetic urine samples. The obtained results were attested by recovery tests and by high-performance liquid chromatography as a comparative technique at a 95% confidence level. Thus, the developed electrochemical sensor is simple and fast to obtain, presents high accuracy, and is viable for determining E2 in routine analysis. Full article
(This article belongs to the Special Issue Advanced Electrochemical Methods in Molecular Detection)
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15 pages, 9302 KiB  
Article
Morphological Effects of Au Nanoparticles on Electrochemical Sensing Platforms for Nitrite Detection
by Ruiqin Feng, Ye Fan, Yun Fang and Yongmei Xia
Molecules 2023, 28(13), 4934; https://doi.org/10.3390/molecules28134934 - 23 Jun 2023
Cited by 1 | Viewed by 879
Abstract
Au nanoparticles were synthesized in a soft template of pseudo-polyanions composed of polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS) by the in situ reduction of chloroauric acid (HAuCl4) with PVP. The particle sizes and morphologies of the Au nanoparticles were regulated [...] Read more.
Au nanoparticles were synthesized in a soft template of pseudo-polyanions composed of polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS) by the in situ reduction of chloroauric acid (HAuCl4) with PVP. The particle sizes and morphologies of the Au nanoparticles were regulated with concentrations of PVP or SDS at room temperature. Distinguished from the Au nanoparticles with various shapes, Au nanoflowers (AuNFs) with rich protrusion on the surface were obtained at the low final concentration of SDS and PVP. The typical AuNF synthesized in the PVP (50 g·L−1)–SDS (5 mmol·L−1)–HAuCl4 (0.25 mmol·L−1) solution exhibited a face-centered cubic structure dominated by a {111} crystal plane with an average equivalent particle size of 197 nm and an average protrusion height of 19 nm. Au nanoparticles with four different shapes, nanodendritic, nanoflower, 2D nanoflower, and nanoplate, were synthesized and used to modify the bare glassy carbon electrode (GCE) to obtain Au/GCEs, which were assigned as AuND/GCE, AuNF/GCE, 2D-AuNF/GCE, and AuNP/GCE, respectively. Electrochemical sensing platforms for nitrite detection were constructed by these Au/GCEs, which presented different detection sensitivity for nitrites. The results of cyclic voltammetry (CV) demonstrated that the AuNF/GCE exhibited the best detection sensitivity for nitrites, and the surface area of the AuNF/GCE was 1.838 times of the bare GCE, providing a linear c(NO2) detection range of 0.01–5.00 µmol·L−1 with a limit of detection of 0.01 µmol·L−1. In addition, the AuNF/GCE exhibited good reproducibility, stability, and high anti-interference, providing potential for application in electrochemical sensing platforms. Full article
(This article belongs to the Special Issue Advanced Electrochemical Methods in Molecular Detection)
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18 pages, 4181 KiB  
Article
Comparative Study on the Sensing Kinetics of Carbon and Nitrogen Nutrients in Cancer Tissues and Normal Tissues Based Electrochemical Biosensors
by Dingqiang Lu, Danyang Liu, Yujiao Liu, Xinqian Wang, Yixuan Liu, Shuai Yuan, Ruijuan Ren and Guangchang Pang
Molecules 2023, 28(3), 1453; https://doi.org/10.3390/molecules28031453 - 02 Feb 2023
Cited by 3 | Viewed by 1379
Abstract
In this study, an electrochemical sensor was developed by immobilizing colon cancer and the adjacent tissues (peripheral healthy tissues on both sides of the tumor) and was used to investigate the receptor sensing kinetics of glucose, sodium glutamate, disodium inosinate, and sodium lactate. [...] Read more.
In this study, an electrochemical sensor was developed by immobilizing colon cancer and the adjacent tissues (peripheral healthy tissues on both sides of the tumor) and was used to investigate the receptor sensing kinetics of glucose, sodium glutamate, disodium inosinate, and sodium lactate. The results showed that the electrical signal triggered by the ligand–receptor interaction presented hyperbolic kinetic characteristics similar to the interaction of an enzyme with its substrate. The results indicated that the activation constant values of the colon cancer tissue and adjacent tissues differed by two orders of magnitude for glucose and sodium glutamate and around one order of magnitude for disodium inosinate. The cancer tissues did not sense sodium lactate, whereas the adjacent tissues could sense sodium lactate. Compared with normal cells, cancer cells have significantly improved nutritional sensing ability, and the improvement of cancer cells’ sensing ability mainly depends on the cascade amplification of intracellular signals. However, unlike tumor-adjacent tissues, colon cancer cells lose the ability to sense lactate. This provides key evidence for the Warburg effect of cancer cells. The methods and results in this study are expected to provide a new way for cancer research, treatment, the screening of anticancer drugs, and clinical diagnoses. Full article
(This article belongs to the Special Issue Advanced Electrochemical Methods in Molecular Detection)
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