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The diazo coupling reaction of diazotized p-aminoacetophenone (DPAAP) with histidine and its metabolites form the basis of the differential pulse adsorption stripping voltammetry (DPASV) method for determination of histidine and its metabolites. The adsorption and electrochemical reaction mechanism of the coupling products were studied in detail by structure analysis, cyclic voltammetry, chronocoulometry,...
The electrochemical reduction of the antidepressant drug fluoxetine was investigated by cyclic, linear sweep, differential pulse and square wave voltammetry using a hanging mercury drop electrode in alkaline buffer solution in water and in a water/acetonitrile mixed solvent. Cyclic voltammograms in aqueous solution showed very strong adsorption of fluoxetine on the electrode with formation of a compact...
The application of two extreme models for diffusion in two-component systems to electrochemically determine equilibrium constants is discussed. The application of cyclic voltammetric, diferential pulse and rotating-disc electrode voltammetric data to elucidate the stoichiometry and formation constant of complex species by applying a generalization of the molar-ratio method is described. Molar-ratio...
As the field of chip-based microscale systems continues its rapid growth, there are urgent needs for developing compatible detection modes. Electrochemistry detection offers considerable promise for such microfluidic systems, with features that include remarkable sensitivity, inherent miniaturization and portability, independence of optical path length or sample turbidity, low cost, low-power requirements...
An electrochemical genomagnetic hybridization assay has been developed to take advantage of a new and efficient magnetic separation/mixing process, the amplification feature of enzyme labels, and single-use thick-film carbon transducers operated in the pulse-voltammetric mode. It represents the first example of coupling a magnetic isolation with electrochemical detection of DNA hybridization. The...
Electrochemical behavior of myoglobin (Mb) incorporated in polyacrylamide (PAM) hydrogel films cast on pyrolytic graphite (PG) electrodes were investigated. Mb-PAM film electrodes showed a pair of well-defined and nearly reversible cyclic voltammetric peaks for Mb Fe(III)/Fe(II) redox couple at about -0.27 (vs. SCE) in pH 5.5 buffers. The electron exchange of Mb with PG electrodes was greatly enhanced...
The electrochemically initiated reaction of aromatic amines with catechol has been examined as a facile route to the electrochemical determination of the former. The effects of the different structural isomers of sulfanilic acid on the analytical system has been studied and appraised. The report illustrates how by varying oxidation times of the catechol species or by increasing the number of repetitive...
Carbon nanotube powder microelectrodes (CNTPMEs) were used to study the anodic oxidation of hydrazine at Carbon nanotube (CNT)-the novel carbon material. It was found that the electrochemical behaviours were greatly improved at CNTs, indicating that the anodic oxidation could be catalyzed at CNTs. The kinetics parameters of this process were calculated, the heterogeneous electron transfer rate constant...
The use of a carbon-nanotube paste (CNTP) electrode provides an effective means for the determination of homocysteine. A decrease of ca. 120mV in the overpotential for the oxidation of homocysteine compared to a traditional carbon paste electrode, is reported along with greatly enhanced signal-to-noise characteristics. The analytical parameters have been assessed with a linear range from 5 to 200μM...
Photoluminescent multilayers were fabricated by layer-by-layer deposition between europium-substituted heteropolytungstate K 13 [Eu(SiW 11 O 39 ) 2 ].28H 2 O (denoted ESW) and a cationic polymer of quaternized poly(4-vinylpyridine) partially complexed with osmium bis(2,2'-bipyridine) (denoted as QPVP-Os) on glassy carbon and quartz substrates...
Direct electrochemistry of hemoglobin (Hb) is observed at carbon nanotube (CNT) interface. The adsorbing Hb can transfer electron directly at CNT interface compared with common carbon material. The heterogeneous electron transfer rate constant k of Hb can be calculated as 0.062s −1 , the transfer coefficient α is 0.21 and the average surface coverage of Hb on CNT surface is 3.58 × 10 −9...
Titanium oxide/phenylphosphonate hybrids were prepared by a two-step sol–gel processing, in the presence of ferrocenylphosphonic acid as an electrochemical probe. We showed that as expected the diffusion of the redox species was related to the kinetics of the sol–gel polymerization. The probable passage through cluster Ti 4 O(O i Pr) 8 (PhPO 3 ) 3 has been confirmed...
The electrochemical behaviour and cation recognition properties of two oxaferrocene cryptand ligands, 1,1′-[(1,4,10-trioxa-7,13-diazacyclopentadecane-7,13-diyl)diethoxy]-3,3′,4,4′-tetraphenylferrocene and 1,1′-[(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)diethoxy]-3,3′,4,4′-tetraphenylferrocene, have been characterized in acetonitrile in the presence of Ba 2+ and Na + by...
Cytochrome c (Cyt. c) was immobilized on the 11-mercaptohendecanoic acid (MUA)-modified gold electrode. The electrode was stable and sensitive to Cyt. c. Later, DNA was also immobilized on the two-layer modified electrode. Cyclic voltammetry studies show that Cyt. c can interact with dsDNA and ssDNA. The binding site sizes were determined to be 15 base pairs per Cyt. c molecule with dsDNA and 30 nucleotides...
During the past decade, significant progress in the development of miniaturized microfluidic systems has occurred due to the numerous advantages of microchip analysis. This review focuses on recent advances and the key strategies in microchip capillary electrophoresis (CE) with electrochemical detection (ECD) for separating and detecting a variety of environmental pollutants. The subjects covered...
This paper reports on a microfluidic device for the flow-injection/electrochemistry analysis of nitroaromatic explosive. The response is very fast (150assays/h), highly sensitive (detection limit 7.0μgL −1 ), reproducible and stable (R.S.D.=2.0%; n=30) and linear (over 20–100μgL −1 range). Relevant experimental parameters have been optimized. The new microsystem offers great promise...
The electrochemical characteristics of a novel all diamond fabricated boron-doped diamond microelectrode array (BDD-MEA) are critically appraised. The voltammetric response of simple electron transfer processes has been investigated and found to generate sigmoidal voltammetric curves. Furthermore, the device has been utilized for various analytical applications including, the direct detection of 4-nitrophenol...
Direct electrochemical and electrocatalytic behavior of hemoglobin (Hb) immobilized on glass carbon electrode (GCE) containing gelatine (Gel) films was investigated. The characteristics of Hb/Gel film modified GC electrode were performed by using SEM microscopy, UV–vis spectroscopy and electrochemical methods. The immobilized Hb showed a couple of quasi-reversible redox peak with a formal potential...
In this study, we investigate highly efficient sonogel carbon electrode (SGC/TiO 2 ) modified with nanostructured titanium dioxide synthesized via sol–gel method employing surfactant template for tailor-designing the structural properties of TiO 2 . The stable SGC/TiO 2 electrode detects catechol, a neurotransmitter, in the presence of ascorbic acid, a common interferent, using...
The development of analytical methods that respond to the growing need to perform rapid ‘in situ’ analyses shows disposable screen-printed electrodes (SPEs) as an alternative to the traditional electrodes. This review presents recent developments in the electrochemical application of disposable screen-printed sensors, according to the types of materials used to modify the working electrode. Therefore,...
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