Efficient grafting of redox-active ferrocene polymers from α,ω-diiodoalkanes at cathodically charged glassy carbon

2012 ◽  
Vol 42 (7) ◽  
pp. 527-537 ◽  
Author(s):  
Viatcheslav Jouikov ◽  
Jacques Simonet
Keyword(s):  
Glassy Carbon ◽  
Redox Active ◽  
Ferrocene Polymers

Selective dopamine detection using aptamer-functionalized glassy carbon electrodes

2015 ◽  
Vol 93 (5) ◽  
pp. 572-577 ◽  
Author(s):  
Ryan Walsh ◽  
Uyen Ho ◽  
Xiao Li Wang ◽  
Maria C. DeRosa
Keyword(s):  
Ascorbic Acid ◽  
Electrochemical Detection ◽  
Glassy Carbon ◽  
Dna Aptamer ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Organic Monolayer ◽  
Dopamine Detection ◽  
Redox Active ◽  
Viable Approach

The electrochemical detection of dopamine using glassy carbon electrodes suffers from a lack of selectivity toward the neurotransmitter, as interferences such as other catechol-containing neurochemicals and ascorbic acid can be oxidized at overlapping potentials. Several approaches have been employed to improve the selectivity of these electrodes towards dopamine including electrochemical pretreatment and organic monolayer depositions. Here, we characterize glassy carbon electrodes that were initially passivated through a trifluoromethylphenyl and nitrophenyl monolayer deposition and then functionalized with a specific DNA dopamine aptamer. Passivation with the mixed monolayer cuts off all signals from the redox-active neurochemicals. After functionalization with the DNA aptamer, the dopamine signal is restored and the electrodes are more responsive to dopamine than to any other related catechol-containing compounds or other common neurochemicals such as ascorbic acid. Our findings indicate that aptamer functionalization of glassy carbon electrodes may provide a viable approach for tuning the selectivity of electrochemical detection.

scholarly journals Impedance aspect of charge storage at graphite and glassy carbon electrodes in potassium hexacyanoferrate (II) redox active electrolyte

2016 ◽  
Vol 6 (1) ◽  
pp. 37 ◽  
Author(s):  
Katja Magdić ◽  
Višnja Horvat-Radošević ◽  
Krešimir Kvastek
Keyword(s):  
Glassy Carbon ◽  
Redox Reaction ◽  
Supporting Electrolyte ◽  
Carbon Electrodes ◽  
Charge Storage ◽  
Potassium Hexacyanoferrate ◽  
Impedance Spectra ◽  
Glassy Carbon Electrodes ◽  
Redox Active ◽  
Diffusion Impedance

<p class="PaperAbstract"><span lang="EN-GB">Different types of charge storage mechanisms at unmodified graphite vs. glassy carbon electrodes in acid sulphate supporting solution containing potassium hexacyanoferrate (II) redox active electrolyte, have been revealed by electrochemical impedance spectroscopy and supported by cyclic voltammetry experiments. Reversible charge transfer of Fe(CN)6<sup>3-/4-</sup> redox reaction detected by assessment of CVs of glassy carbon electrode, is in impedance spectra indicated by presence of bulk diffusion impedance and constant double-layer/pseudocapacitive electrode impedance compared to that measured in the pure supporting electrolyte. Some surface retention of redox species detected by assessment of CVs of graphite electrode is in impedance spectra indicated by diffusion impedance coupled in this case by diminishing of double-layer/pseudo­capacitive impedance compared to that measured in the pure supporting electrolyte. This phenomenon is ascribed to contribution of additional pseudocapacitive impedance generated by redox reaction of species confined at the electrode surface.</span></p>

Electrochemical fabrication of one-dimensional porphyrinic wires on electrodes

2016 ◽  
Vol 3 (3) ◽  
pp. 370-375 ◽  
Author(s):  
Suzaliza Mustafar ◽  
Kuo-Hui Wu ◽  
Ryojun Toyoda ◽  
Kenji Takada ◽  
Hiroaki Maeda ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Conjugated Polymer ◽  
One Dimensional ◽  
Redox Active ◽  
Electrochemical Fabrication

[5,15-Di(4-aminophenyl)-10,20-diphenylporphyrinato]zinc(ii) was found to electropolymerize on electrodes such as glassy carbon (GC), indium tin oxide (ITO), and tin oxide, to form a redox-active, stable, and reproducible π-conjugated polymer.

Electron-diffraction studies of amorphous carbon thin films

1993 ◽  
Vol 51 ◽  
pp. 1100-1101
Author(s):  
David A. Muller
Keyword(s):  
Thin Films ◽  
Electron Diffraction ◽  
Amorphous Carbon ◽  
Glassy Carbon ◽  
Spherical Structure ◽  
Local Ordering ◽  
Carbon Arc ◽  
Similar Appearance ◽  
Carbon Thin Films ◽  
Large Spherical

The sp2 rich amorphous carbons have a wide variety of microstructures ranging from flat sheetlike structures such as glassy carbon to highly curved materials having similar local ordering to the fullerenes. These differences are most apparent in the region of the graphite (0002) reflection of the energy filtered diffracted intensity obtained from these materials (Fig. 1). All these materials consist mainly of threefold coordinated atoms. This accounts for their similar appearance above 0.8 Å-1. The fullerene curves (b,c) show a string of peaks at distance scales corresponding to the packing of the large spherical and oblate molecules. The beam damaged C60 (c) shows an evolution to the sp2 amorphous carbons as the spherical structure is destroyed although the (220) reflection in fee fcc at 0.2 Å-1 does not disappear completely. This 0.2 Å-1 peak is present in the 1960 data of Kakinoki et. al. who grew films in a carbon arc under conditions similar to those needed to form fullerene rich soots.

Common modifications of selenocysteine in selenoproteins

2019 ◽  
Vol 64 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Elias S.J. Arnér
Keyword(s):  
Amino Acids ◽  
Covalent Binding ◽  
Physicochemical Characteristics ◽  
Redox Active

Abstract Selenocysteine (Sec), the sulfur-to-selenium substituted variant of cysteine (Cys), is the defining entity of selenoproteins. These are naturally expressed in many diverse organisms and constitute a unique class of proteins. As a result of the physicochemical characteristics of selenium when compared with sulfur, Sec is typically more reactive than Cys while participating in similar reactions, and there are also some qualitative differences in the reactivities between the two amino acids. This minireview discusses the types of modifications of Sec in selenoproteins that have thus far been experimentally validated. These modifications include direct covalent binding through the Se atom of Sec to other chalcogen atoms (S, O and Se) as present in redox active molecular motifs, derivatization of Sec via the direct covalent binding to non-chalcogen elements (Ni, Mb, N, Au and C), and the loss of Se from Sec resulting in formation of dehydroalanine. To understand the nature of these Sec modifications is crucial for an understanding of selenoprotein reactivities in biological, physiological and pathophysiological contexts.

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