The self-assembled iodine-adlayer was fabricated at the palladium (Pd) electrode surface throughout a spontaneous oxidative chemisorption of iodide ions contained in an alkaline supporting electrolyte. It enhances the electron transfer kinetics for the oxidation of dopamine (DA) and ascorbic acid (AA) and was important to separate the peak current of both species with a practical potential difference compared with that occurred at the unmodified electrode. The anodic peak currents of both species were linearly increased with their respective concentrations using linear square stripping voltammetry. The activity of the electrode system was further investigated applying chronoamperometry method. The steady-state amperometric signal for the oxidation of DA in the presence of iodide ions was five times greater than that in its absence. The current-time response was also used to evaluate the diffusion coefficient of DA based on Cottrell plot that results with a value of 4.19 x 10(-8)m(2)s(-1). The proposed method was successfully applied to detect DA and AA in human serum.
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http://dx.doi.org/10.1016/j.talanta.2009.10.044 | DOI Listing |
Molecules
January 2025
Department of Chemistry and Biochemistry, University of Colorado, Colorado Springs, CO 80918, USA.
Catalytically active nanomaterials, or nanozymes, have gained significant attention as alternatives to natural enzymes due to their low cost, ease of preparation, and enhanced stability. Because of easy preparation, excellent biocompatibility, and unique optoelectronic properties, gold nanoparticles (AuNPs) have attracted increasing attention in many fields, including nanozymes. In this work, we demonstrated the applicability of beta-cyclodextrin functionalized gold nanoparticles (β-CD-AuNPs) as enzyme mimics for different substances, including TMB and DA.
View Article and Find Full Text PDFMolecules
January 2025
Department of Chemistry, Middle Tennessee State University, 440 Friendship Street, Murfreesboro, TN 37132, USA.
Elevated dopamine (DA) levels in urine denote neuroblastoma, a pediatric cancer. Saccharide-derived carbon dots (CDs) were applied to assay DA detection in simulated urine (SU) while delineating the effects of graphene defect density on electrocatalytic activity. CDs were hydrothermally synthesized to vary graphene defect densities using sucrose, raffinose, and palatinose, depositing them onto glassy carbon electrodes (GCEs).
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January 2025
Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Panduri Avenue 90-92, District 5, 050663 Bucharest, Romania.
This paper summarizes the main findings of a study which aimed to examine the electrochemical oxidation of homovanillic acid (HVA), the final metabolite of dopamine. A pencil graphite electrode (PGE) was used as working electrode and the measurements were performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The type and the composition of the graphite leads used as PGE, the pH of the supporting electrolyte, as well as the scan rates were optimized by CV.
View Article and Find Full Text PDFBiomolecules
December 2024
Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2G3, Canada.
Schizophrenia is a complex heterogenous disorder thought to be caused by interactions between genetic and environmental factors. The theories developed to explain the etiology of schizophrenia have focused largely on the dysfunction of neurotransmitters such as dopamine, serotonin and glutamate with their receptors, although research in the past several decades has indicated strongly that other factors are also involved and that the role of neuroglial cells in psychotic disorders including schizophrenia should be given more attention. Although glia were originally thought to be present in the brain only to support neurons in a physical, metabolic and nutritional capacity, it has become apparent that these cells have a variety of important physiological roles and that abnormalities in their function may make significant contributions to the symptoms of schizophrenia.
View Article and Find Full Text PDFPhytother Res
January 2025
Constantine the Philosopher University in Nitra, Nitra, Slovak Republic.
This narrative review describes the provenance and chemical composition of Vitex agnus-castus, as well as the currently available knowledge concerning its action. To search the related articles, Cochrane Library, PubMed, Web of Science, SCOPUS databases between the years 1995 and 2024, and the keywords "Vitex," "review," "fertility," "ovarian" and "mechanisms" were used in various combinations. The data listed in this review demonstrate that Vitex agnus-castus and its constituents (isoflavones and essential oils) affect a number of physiological actions via multiple extra- and intracellular mechanisms of action.
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