A modified electrode consisting of copper dispersed in a poly-1-naphthylamine (p-1-NAP/Cu) film on a glassy carbon electrode was used as an amperometric detector for the on-line analysis of various carbohydrates separated by high performance liquid chromatography. The results obtained with this new sensor were compared to those obtained with a modified electrode based on the same polymer but with copper ions incorporated at open circuit, as described in a previous paper. In this new modified electrode the copper microparticles were electrochemically deposited into the polymeric matrix by single potential step chronoamperometry. A nucleation and growth mechanism was proposed to explain the current transients of copper electrodeposition. The experimental results were fitted to the proposed mechanism by using a mathematical equation that considers three-dimensional growth and progressive nucleation, assuming a no overlap and no diffusion mechanism. Cyclic voltammetric experiments showed that the electrodeposited copper microparticles provided a catalytic surface suited for the oxidation of glucose and several carbohydrates. The sensitivity of the electrode was influenced by the amount of copper electrodeposited, which in turn depended on the applied overpotential used for the deposition of copper. Liquid chromatographic experiments were carried out to test the analytical performance of these electrodes for the determination of various carbohydrates.
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http://dx.doi.org/10.1016/S0039-9140(03)00304-7 | DOI Listing |
Rev Sci Instrum
January 2025
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410072, China.
High power pulse generators are moving in the direction of compact, solid-state, and stable working in a relatively long time. In this paper, a compact pulse forming line-Marx type high power pulse generator, based on a ceramic pulse forming line and a spark gap switch with carbide modified graphite electrodes, is studied numerically and experimentally. Specifically, a ceramic based pulse forming line with high relative permittivity was used to achieve long pulse duration in a limited dimension.
View Article and Find Full Text PDFBiotechnol Appl Biochem
January 2025
Department of Gastrointestinal Surgery, The Fifth People's Hospital of Jinan, Jinan, Shandong, China.
Ulcerative colitis affects the inner lining of the large intestine, causing discomfort, pain, and digestion issues, and sometimes leading to life-threatening complications. With proper medication, symptoms and inflammation can be reduced, improving the condition. In this research, a multiwalled carbon nanotube (MWCN)-modified circular interdigitated electrode (circular-IDE) biosensor was developed to detect the ulcerative colitis biomarker lipocalin-2 and measured at 0-2 V.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Chemistry Department, Faculty of Science, Ain-Shams University, Cairo, 11566, Egypt; Department of Chemistry, Faculty of Science, Galala University, New Galala City, Suez, Egypt. Electronic address:
Background: Electrochemical methods, particularly those utilizing sensors, offer distinct advantages over classical analytical methods. They are cost-effective, compatible with mass fabrication, suitable for remote sensing, and can be designed as handheld analyzers. In this context, MIL-101(Cr)-(COOH)₂@MWCNTs was utilized for the first time as a modifier for GCE for the sensitive voltammetric detection of Pb(II), Cu(II), and Hg(II).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States.
The widespread use of gadolinium-based contrast agents for magnetic resonance imaging (MRI) in recent decades has led to a growing demand for Gd and raised environmental concerns due to their direct discharge into wastewater systems. In response, we developed an electrochemical filtration method to recover Gd from patient urine following contrast-enhanced MRI. This method involves modifying a conventional vacuum filtration apparatus by introducing electrodes into the filter membrane, creating a strong electric field of ∼5 kV/m and a steep three-zone pH gradient within the filter membrane.
View Article and Find Full Text PDFAnal Methods
January 2025
School of Pharmacy, Wannan Medical College, Wuhu 241002, China.
A label-free photoelectrochemical (PEC) sensor for detecting theophylline (TP) was exploited based on electrodes modified with a nanocomposite of polydopamine nanospheres (PDSs) and gold nanoparticles (AuNPs). PDS particles were prepared by oxidative autopolymerization, and their reducibility was utilized in one step to reduce the gold nanoparticles . The AuNPs-PDS/ZnS PEC sensor was constructed by electrochemical deposition and drop coating.
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