Electropolymerization of Meldola Blue was carried out by cyclic voltammetry in the range from -0.6 to +1.4 V vs. Ag/AgCl, thus defining a new immobilization procedure of the phenoxazine mediator on screen-printed graphite electrodes. Evidence of polymer formation was provided by electrochemical and Fourier transform infrared spectroscopy (FTIR) data. Following polymerization, Meldola Blue preserved the ability to catalyze NADH oxidation allowing to achieve a detection limit of 2.5 x 10(-6) mol l(-1) and a sensitivity of 3713 microA l mol(-1) in amperometric determinations at 0 V vs. Ag/AgCl. In addition, the polymeric mediator was found to facilitate the reduction of hydrogen peroxide in the absence of peroxidase. Typical calibration at -0.1 V vs. Ag/AgCl shows a detection limit of 8.5 x 10(-5) mol l(-1), a sensitivity of 494 microA l mol(-1) and a linear range from 2.5 x 10(-4) to 5 x 10(-3) mol l(-1) hydrogen peroxide.
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http://dx.doi.org/10.1016/s0956-5663(03)00044-7 | DOI Listing |
Analyst
January 2025
College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
A novel electrochemical microsensor was constructed on a traditional acupuncture needle (AN) and used to monitor a biomarker of the SARS-CoV-2-N protein. The reversible interaction of the borate bond between the -diol in this glycoprotein and the phenylboronic acid in 4-mercaptophenylboronic acid (4-MPBA) was accomplished. This interaction was applied to anchor the SARS-CoV-2-N protein onto 4-MPBA, which was covalently self-assemblied onto electrodeposited AuNPs by the S-Au bond.
View Article and Find Full Text PDFAnal Chem
November 2024
Department of Chemistry and Biochemistry, Clarkson University, Potsdam, New York 13699, United States.
Per- and polyfluoroalkyl substances (PFAS) are highly stable ubiquitous contaminants that have been recently added to the list of regulated chemicals. While methods for PFAS detection exist, analysis is difficult, involving a tedious protocol and expensive instrumentation. Here, we demonstrate the first implementation of a phenoxazine dye as a sensing probe that facilitates rapid and inexpensive detection of representative PFAS, e.
View Article and Find Full Text PDFTalanta
May 2024
Institute of Electrochemistry, University of Alicante, 03080, Alicante, Spain; Department of Physical Chemistry, University of Alicante, 03080, Alicante, Spain.
The biggest allure of heterogeneous electro-Fenton (HEF) processes largely fails on its high efficiency for the degradation of a plethora of hazardous compounds present in water, but still challenging to search for good and cost-effective electrocatalyst. In this work, carbon black (CB) and oxidised carbon black (CBox) materials were investigated as cathodes in the electrochemical production of hydrogen peroxide involved in HEF reaction for the degradation of 2-phenylphenol (2PP) as a target pollutant. The electrodes were fabricated by employing carbon cloth as support, and the highest HO production yields were obtained for the CBox, pointing out the beneficial effect of the hydrophilic character of the electrode and oxygen-type functionalization of the carbonaceous surface.
View Article and Find Full Text PDFAnal Biochem
November 2022
Departamento de Biologia, Universidade Estadual do Maranhão, CEP 65080-805 São Luís, MA, Brazil.
In the present study, the objective was to evaluate in situ interaction between Benzo[a]anthracene 7,2-dione 7-oxime (BZA) and calf thymus dsDNA (ct-dsDNA) using electroanalytical genosensor. Analytical techniques based on Ultraviolet/Visible (UV-Vis) spectroscopy and electroanalytical were used to investigate the interaction processes in solution and immobilized on carbon screen-printed electrodes modified with electrochemical mediator Meldola blue. In addition, was possible to evaluate the degree of damage caused to the genetic material by the analyte through of toxicity estimate (S%).
View Article and Find Full Text PDFAntioxidants (Basel)
February 2021
Pesticide Residue Analysis Center, Federal University of Maranhão, UFMA. Av. Portugueses, CCET, Bacanga, CEP, São Luis, MA 65080-040, Brazil.
Antioxidants are synthetic or natural compounds capable of preventing or delaying oxidative damage caused by chemical species that can oxidize cell biomolecules, such as proteins, membranes, and DNA, leading to the development of various pathologies, such as cancer, atherosclerosis, Parkinson, Alzheimer, and other diseases serious. In this study, an amperometric biosensor was used to determine the antioxidant activity of teas and effervescent products based on vitamin C, available on the market. A sensor composed of three electrodes was used.
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