bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorptive stripping voltammetry of anionic surfactants on a carbon paste electrode using ferrocenyl cationic surfactant as an analytical electrochemical probe
Authors: Hattori Toshiaki , Kato Masanao , Tanaka Shunitz , Hara Minoru 
Published: May 2005

AbstractAdsorption stripping voltammetry (AdSV) for anionic surfactants was examined, based on ion association with an electroactive ferrocenyl cationic surfactant. The ion association complex between an anionic surfactant and a ferrocenyl cationic surfactant accumulated on the carbon paste electrode (CPE) in the absence of an applied potential. The concentration of anionic surfactant was indirectly evaluated from the oxidation wave of the ferrocenyl cationic surfactant. By means of AdSV, levels of anionic surfactants of 10−7 mol dm−3 could be measured with good selectivity. The role of pasting liquids on the accumulation behavior of ferrocenyl TMA were examined by a comparison of two pasting liquids. The first, 2‐nitrophenyl octyl ether (NPOE) was capable of extracting the ferrocenyl TMA salt, while the other, di‐n‐octylphthalate (DOP) was not. The voltammograms of ferrocenyl TMA varied considerably with the pasting liquids. In particular, the peak potentials at NPOE‐CPE gradually shifted with time, as a result of the extraction of the ferrocenyl TMA salt into the CPE. However, the peak potential at DOP‐CPE remained constant.
Electrochemical study of methylene blue immobilized in zirconium phosphate
Authors: Pessôa Christiana A. , Gushikem Yoshitaka , Kubota Lauro T. 
Published: May 2005

AbstractMethylene Blue (MB) was adsorbed in zirconium(IV) phosphate by means of an ion exchange reaction. The dye is strongly retained and not easily leached from the matrix. The material with the adsorbed dye was incorporated into a carbon paste electrode and by means of cyclic voltammetry and amperometry, the electrochemical property was investigated. In various electrolyte solutions and changing the pH between 2.5 and 6, the midpoint potential remained practically constant, i.e., 0.15 ± 0.01 V. This is not the usual behavior of MB, since it is known in solution phase that its midpoint potential changes considerably as the pH changed. It appears that the Methylene Blue is a guest molecule in the lamellar structure of the zirconium phosphate. The electrode made with this material was used to study the electrochemical oxidation of ascorbic acid.
Prediction and characterization of the charge/size exclusion properties of over‐oxidized poly(pyrrole) films
Authors: Farrington Amiel M. , Slater Jonathan M. 
Published: May 2005

AbstractOver‐oxidation of poly(pyrrole) films has been shown to result in permselective films favoring cation transport and excluding anions. The exclusion principal depends on both the size of the analyte and electrostatic interactions between the analyte and the polymer film. The size of the polymer dopant anion and hence the resulting pore size of the polymer has been varied and the size exclusion studied. Molecules just larger than the size of the original dopant anion can pass through the membrane, thought to be due to solvation of the incorporated anion in the initial polymer preparation. The pH of the sample analyte has been varied to test the permselective properties of the prepared polymer. A range of substituted pyrroles were polymerized, over‐oxidized and compared for selectivity. The nature and position of substituents on the pyrrole monomer were observed to change the morphological structure of the polymer and hence the resulting selectivity of the membrane. Molecular modeling of both the analytes and the dopant ions has allowed size/charge density profiles of the analytes to be compared with the predicted size of the polymer pores.
Hydrodynamic microelectrodes. The microdisk electrode: Theory and experiment
Authors: Fisher Adrian C. , Davies C. W. , Fulian Q. , Walters M. 
Published: May 2005

AbstractA computationally efficient fully implicit approach to the simulation of linear sweep and potential step voltammetry at a channel microdisk electrode is derived. The generality of the method is illustrated with reference to the simple case of a reversible one electron transfer reaction. The influence of flow rate and the effects of axial, lateral and normal diffusion upon the electrolysis current are quantified. Scan rate and electrode geometry dependences are established and the requirements for measurement of true steady state hydrodynamic voltammograms defined.
A new membrane sensor for UO ions based on 2‐hydroxyacetophenoneoxime‐thiourea‐trioxane resin
Authors: Jain A. K. , Gupta V. K. , Khurana U. , Singh Lok P. 
Published: May 2005

AbstractPoly(vinylchloride) (PVC) and polystyrene based uranyl ion‐selective electrodes have been constructed using 2‐hydroxyacetophenoneoxime‐thiourea‐trioxane resin as electroactive material. For PVC based membranes dibutylphthalate (DBP) and dioctylphthalate (DOP) were used as plasticizing solvent mediators. These membrane electrodes work in the concentration range of ca. 10−5–10−1 M with a response time as fast as 30 s. The useful working pH range is 2.5–3.5 and the electrodes perform satisfactorily up to 20 % (v./v.) partially nonaqueous content. The electrodes were used over a period of 4 months with good reproducibility (standard deviation = 0.5 mV). Further, the selectivity coefficient values of the order 0.1 for mono‐ and bivalent ions indicate moderate selectivity for UO ions over the interfering ions.
Electroanalytical determination of styrene in acrylonitrile‐butadiene‐styrene copolymers
Authors: Geraldo M. Dulce , Montenegro M. Irene 
Published: May 2005

AbstractThe analysis of residual styrene in terpolymers of acrylonitrile, butadiene and styrene (ABS) by a rapid electroanalytical method is described. The sample is simply dissolved in N, N‐dimethylformamide containing an excess of electrolyte and analysed by square wave voltammetry on a gold microdisk electrode; the styrene content is determined using the standard addition technique.
XPS analysis of hydroxide ion surface reactions on reactions on CeF3 and LaF3 fluoride ion‐selective electrodes
Authors: Shen W. , Wang X. D. , Cattrall R. W. , Nyberg G. L. , Liesegang J. 
Published: May 2005

AbstractLanthanum fluoride and cerium fluoride single crystals, used as the sensing membranes of the fluoride ion‐selective electrode (F‐ISE), were investigated for their hydroxide interference and surface reactions with OH− in high pH conditions. While these membranes show fast response and excellent Nernstian behavior over a wide concertration range in buffered F− solutions, they deviate from the theoretical slope at high pH. CeF3, in particular, exhibits a much larger deviation from the Nernstian slope and a substantially slower response to a F− activity change compared to LaF3. This larger deviation is due to more extensive and faster formation of hydroxo‐complexes, with the release of a greater amount of the fluoride ion into the hydrated gel layer. The slower response of the CeF3 membrane after contact with OH− is due to the formation of CeIV oxide on the surface, which acts as a blocking layer to the exchange of F−.
A graphite silver(I) hexacyanoferrate(III) composite electrode for the determination of iron (III) ions
Authors: Kahlert Heike , Scholz Fritz 
Published: May 2005

AbstractA reactive electrode (reactrode) made of silver(i) hexacyanoferrate(III) (Ag‐hcf), graphite and paraffin has been developed for the determination of iron(III) ions in solutions down to a concentration of 0.12 mg L−1. Silver ions are reduced to Ag0 and the liberated hecacyanoferrate ions react with iron(III) ions from the solution to form Prussian blue. After this preconcentration step, the iron ions can be determined electrochemically by the characteristic signals of Prussian blue in differential pulse voltammetry. A nonlinear calibration plot is obtained which has a standard deviation of 13%. Pb2+, Cu2+ and Ni2+ interfere when they are at the same concentration as iron(III), whereas Cd2+ does not interfere even at higher concentrations. The incorporation of an active reagent into the electrode material remarkably facilitates the analytical procedure and makes the use of a mercury electrode unnecessary.
The electrochemical determination of N‐nitrosamines at polymer modified electrodes via an adsorptive stripping voltammetric regime
Authors: Collyer Stuart D. , Butler Alastair J. , Higson Séamus P. J. 
Published: May 2005

AbstractAn adsorptive linear sweep stripping voltammetric method has been developed for the determination of nitrosamines at polymer modified gold electrodes. N‐nitroso‐N‐butyl‐N‐propylamine has been quantified over a 10−10 M to 10−6 M concentration range at Nafion modified electrodes. CA coatings inhibited the determination of N‐nitroso‐N‐butyl‐N‐propylamine, while small enhancements were observed at CAB modified electrodes. This improvement may be due to the anionic butyrate groups within the CAB polymer facilitating nitrosamine sorption. It is postulated, that the insulating effect of the polymer and the incorporation of anionic moieties compete to give either a net enhancement or depreciation of analytical sensitivity.
Peroxidase‐glucose oxidase‐poly(amphiphilic pyrrole) bioelectrode for selectively mediated amperometric detection of glucose
Authors: Popescu Ionel C. , Cosnier Serge , Labbé Pierre 
Published: May 2005

AbstractMonoenzyme (HRP) and bilyer/monolayer bienzyme (HRP‐GOX) bioelectrodes were realized by the oxidative electropolymerization of amphiphilic pyrrole monomer 1 enzyme(s) mixtures, previously adsorbed on the surface of a glassy carbon electrode. Cyclic voltammetry measurements, carried out on poly 1‐HRP modified electrodes showed that the electrocatalytical reduction of H2O2, in the presence of K4Fe(CN)6 as mediator, occurs at applied potentials well placed in the optimal potential range for amperometric detection. An optimization study concerning the mediator concentration, the amount of the immobilized enzyme(s), the electrode material and the matrix structure (mono‐ or bilayer) was performed in order to obtain the glucose biosensor. At an applied potential of −0.1 V (vs. SCE), batch amperometric response to H2O2 for the HRP modified electrodes gave a sensitivity of ca. 280 mA M−1 cm−2 (up to 0.65 mM). For monolayer biosensor the sensitivity to glucose was ca. 170 mA M−1 cm−2 (up to 1.9 mM). The interference of ascorbate, urate and acetaminophen was found almost negligible.
Rotating disk electrode voltammetry/anodic stripping voltammetry for chemical speciation of lead and cadmium in freshwaters containing dissolved organic matter
Authors: Lam Michael T. , Chakrabarti C. L. , Cheng J. , Pavski V 
Published: May 2005

AbstractRotating disk electrode voltammetry (RDEV) in conjunction with anodic stripping voltammetry (ASV) with a thin mercury film electrode (TMFE) or with a Nafion‐coated thin mercury film electrode (NCTMFE) has been evaluated for the direct determination (i.e., without preconcentration) of lead and cadmium speciation in aqueous solutions containing dissolved organic matter. The RDEV technique has been used to estimate dissociation rate constants and diffusion coefficients; pseudopolarograms have indicated the identity of the metal complexes undergoing electrode reductions at the corresponding plateaus of the pseudopolarograms in a number of model solutions containing Cd or Pb and known amounts of fulvic acid. It has been found that the effect of dissolved organic material is measurable when the concentrations of fulvic acid are equal to or less than 20 μg/mL (which is below the concentration of naturally occurring dissolved organic carbon in most freshwaters). The effective electrode surface area has been found to be considerably less than the geometric surface area, and if this fact is not explicitly taken into consideration, the result would be an erroneous estimation of dissociation rate constants and diffusion coefficients. Pseudopolarograms of aqueous samples containing Cd or Pb and fulvic acid and samples of Rideau river surface water clearly show that NCTMFEs effectively block the transport of large inert metal‐FA complexes to the electrode surface, resulting in interference‐free determination, and giving well‐defined pseudopolarograms, and yet do not hinder the transport of small metal‐FA complexes to the electrode surface. It is concluded that RDEV/ASV offers promise of being a valuable technique for determining chemical speciation of lead and cadmium in river surface waters.
Carbon packed‐bed upstream electrode in combination with a downstream thin‐layer cell for dual electrode applications in microbore liquid chromatography and flow injection analysis
Authors: Jayaratna H. G. , Yang Liu , Huang T. , Bruntlett C. S. , Kissinger P. T. 
Published: May 2005

AbstractA flow‐through electrode with a high conversion efficiency has been developed for chromatographic detection as well as other on‐line electrochemical applications. A small length of reticulated vitreous carbon material of high pore density permits excellent conversion of so ne organic compounds. This can easily be employed in dual electrode applications with radial or cross flow thin‐layer detectors. When used as a generator electrode, it can improve selectivity for electrochemically active compounds in chromatographic detection and microdialysis/biosensor combinations.
Immobilization of methylene blue using α‐zirconium phosphate and its application within a reagentless amperometric hydrogen peroxide biosensor
Authors: Ruan Chuanmin , Yang Feng , Xu Jinsuo , Lei Chengheng , Deng Jiaqi 
Published: May 2005

AbstractA novel H2O2 sensor was constructed by employing methylene blue (MB) incorporated in α‐zirconium phosphate as an electron transfer mediator. Methylene blue was intercalated into a α‐zirconium phosphate modified horseradish peroxidase (HRP) immobilization matrix cross‐linked on a glassy carbon electrode surface via bovine serum albumin (BSA)‐glutaraldehyde. Such a coimmobilization matrix of the mediator and enzyme was formed from α‐zirconium phosphate‐MB inclusion colloid in which horseradish peroxidase was dissolved. Intercalation of methylene blue in layered α‐zirconium phosphate was investigated by X‐ray power diffraction (XRD), IR spectra and electrochemical measurements. Methylene blue immobilized in this way underwent a quasi‐reversible electrochemical redox reaction. Cyclic voltammetry and amperometric measurements demonstrated that methylene blue coimmobilized with HRP displayed good stability and efficiently shuttled electrons between HRP and the electrode. The sensor responded rapidly and linearly to H2O2 over the range from 2.0 × 10−6 to 5.0 × 10−3 mol/L, with a detection limit of 3.0 × 10−7 mol/L.
Electrocatalytic oxidation and flow amperometric detection of hydrazine at an electropolymerized 4‐vinylpyridine/palladium film electrode
Authors: Li Tao , Wang Erkang 
Published: May 2005

AbstractA poly(4‐vinyl)pyridine (PVP)/Pd film electrode was constructed for the electrocatalytic detection of hydrazine. The preparation of the PVP/GC electrode was performed by electropolymerization of the monomer 4‐vinylpyridine onto the surface of a glassy carbon electrode. Subsequently, palladium is electrodeposited onto the polymer modified electrode surface. The ion‐exchange function of PVP polymer is helpful to this process in view of the tetrachlorapalladate anion. Compared with the Pd/GC electrode, the modified electrode displays a better mechanical stability in a flowing stream. The PVP/Pd film electrode exhibits higher sensitivity when detecting hydrazine with a detection limit of 0.026 ng (S/N=3).
Time differential surface plasmon resonance measurements applied for electrochemical analysis
Authors: Iwasaki Yuzuru , Horiuchi Tsutomu , Morita Masao , Niwa Osamu 
Published: May 2005

AbstractThe processes of oxide film formation and ion adsorption on gold electrodes were monitored by the simultaneous measurement of electrochemical potential scanning voltammetry and surface plasmon resonance (SPR) condition. The time differential of the SPR incident angle was used for the analysis of the surface reactions of the gold electrode. Each stage of oxide film formation on the sputtered gold electrodes and anion adsorption/desorption was clearly detected by this method and directly correlated to the current. SPR is sensitive to the surface adsorbate while the electrode current reflects the overall electrochemical process. This difference was used to separate adsorption from the diffusion process under different hydrodynamic conditions.
Alkylated cyclodextrin‐based potentiometric and amperometric electrodes applied to the measurement of tricyclic antidepressants
Authors: Kataky Ritu , Palmer Simon , Parker David , Spurling Dominic 
Published: May 2005

AbstractAlkylated α, β and γ cyclodextrins have been incorporated in ion‐selective electrodes as neutral ionophores and used for the detection of the tricyclic antidepressants imipramine, desipramine and trimipramine as their hydrochloride salts. Nernstian response and excellent potentiometric limits of detection were observed with each of the three alkylated cyclodextrins examined. Interference from ‘serum’ levels of Na+, K+ and Ca2+ ions was very low. Interference from organic molecules such as glycine, L‐histidine and nicotinamide was also low in most cases (see text for exceptions). Electrodes suitable for amperometric measurements were assembled by depositing alkylated cyclodextrins on screen printed electrode substrates. Inclusion of the tricyclic antidepressants in the cyclodextrin cavity aided by controlled potential electrolysis, allowed subnanomolar levels of the analyte to be monitored by square wave voltammetry. Mechanistic studies indicated that, by preconditioning the modified electrodes at approximately +0.6 V in phosphate buffer, the appropriate radical cation was formed, which, on further conditioning at approximately −0.2 V rapidly formed the dimer which possessed a lower oxidation potential of approximately +0.18 V. Monitoring the redox wave at 0.18 V afforded a powerful analytical handle for trace analysis of these tricyclic antidepressants. This redox wave is observable only in the presence of aqueous phosphate which may be attributed to the formation of a hydrogen‐bonded surface ion‐pair including the substrate and a phosphate counterion.
Characteristics of copper(II) ion‐selective electrode based on aquatic humic substances
Authors: Lu Xiaoqiao , Yang Xinhao , Chen Zuliang 
Published: May 2005

AbstractA carbon rod electrode coated with a poly(vinyl chloride) (PVC) membrane containing aquatic humic substances (HS) isolated from swamp water was constructed for the detection of copper(II) ion. The electrode exhibits a linear response with a slope of 60.1 ± 2.0 mV/decade in concentration range from 10−5 mol L−1 to 10−2 mol L−1. The detection limit for the copper(II) ion was estimated to be of 1 × 10−5 mol L−1. Electron spin resonance spectroscopy (ESR) and pH titration results indicated that the humic substances interact with copper(II) ions to form complexes. These results confirm that the potential response of the membrane electrode with good sensitivity, selectivity except for Pb2+ and Hg2+, and response to copper(II) ion is due to the formation of stable complexes occurring at the electrode surface.
Solid‐state sodium‐selective sensors based on screen‐printed Ag/AgCl reference electrodes
Authors: Walsh S. , Diamond Dermot , McLaughlin J. , McAdams E. , Woolfson D. , Jones D. , Bonner M. 
Published: May 2005

AbstractThe potentiometric and AC impedance characteristics of all solid‐state sodium‐selective electrodes based on planar screen‐printed Ag/AgCl electrodes are described. Two solid‐state designs have been investigated. The first was based on the deposition of a sodium‐selective PVC membrane directly on top of a screen‐printed Ag/AgCl electrode. The second design included a NaCl doped hydrogel layer, between the PVC and Ag/AgCl layers. The hydrogel provides a mechanism to relieve any blockage to charge transfer occurring when PVC membranes are used directly on top of Ag/AgCl and also improves adhesion between the two layers. Results suggest the electrodes display fast ion exchange kinetics, low noise and drift. The performance compares favorably to that of a conventional ion‐selective electrode with internal filling solution.
Derivative adsorption chronopotentiometric determination of aluminum in natural and drinking waters using the AlIII‐1,2‐dihydroxyanthraquinone‐3‐sulfonic acid system
Authors: Bi Shuping , Yu Jiong 
Published: May 2005

AbstractAn absorptive chronopotentiometric method was developed for the determination of trace aluminum. The method relies on the adsorptive accumulation of a AlIII‐1,2‐dihydroxyanthraquinone‐3‐sulfonic acid complex on the surface of a hanging mercury drop electrode. The optimum experimental conditions with respect to pH. preconcentration potential, preconcentration time and concentration of 1,2‐dihydroxyanthraquinone‐3‐sulfonic acid have been investigated. The suggested procedure has been used for the determination of aluminum in natural and drinking water samples and the accuracy investigated by comparison with results obtained by atomic absorption spectrometry.
Differential pulse adsorptive anodic stripping voltammetric determination of pipemidic acid in tablets at a carbon fiber microdisk electrode
Authors: He Ya‐Nan , Chen Hong‐Yuan 
Published: May 2005

AbstractAn adsorptive anodic stripping voltammetric determination of pipemidic acid (PPA) in tablets with a carbon fiber microdisk electrode is presented. A sensitive differential pulse adsorptive anodic stripping peak of PPA was found at 1.06 V (vs. Ag/AgCl) in pH 7.0 phosphate buffer solutions. Under the optimal conditions (buffer solution: pH 7.0 0.20 mol/L PBS, accumulation time: 30s, accumulation potential: 0.10V, pulse height: 80 mV, pulse width: 80ms) the height of the peak linearly increased with the concentration of PPA in the range of 2.8 × 10−7–1.2 × 10−6 mol/L. The method is not affected by oxygen, no extraction was required before the voltammetric analysis, and the excipients present in the PPA tablets show no interference with the analysis. The method was used for the determination of PPA in tablets with satisfactory results.
Protein kinase C subspecies distinguish major cell types in rat hippocampus: An immunocytochemical and in situ hybridization histochemical study
Authors: McGinty Jacqueline F. , Couce Marta E. , Bohler William T. , Ways D. Kirk 
Published: May 2005

AbstractThis study compares the distribution of protein kinase C (PKC) α and β with the distribution of PKC ∈ in the hippocampal formation of rats by immunocytochemistry and in situ hybridization histochemistry. Alpha and PKC β are members of the group A PKC genes that were first described; PKC ∈ is a member of the group B PKC genes that were more recently identified by molecular cloning. A combination of all three gene products and their mRNAs overlapped in their distributions in dentate granule cells and pyramidal and nonpyramidal neurons. However, each subspecies predominated in one of the major cell types. PKC α‐immunoreactivity and mRNA were most intense in CA2‐3 pyramidal cells and dendrites, whereas PKC β‐immunoreactivity and mRNA were most intense in CA1 pyramidal cells and dendrites. PKC ∈‐immunoreactivity and mRNA were concentrated in dentate granule cells and CA3 pyramidal cells. Furthermore, PKC ∈‐immunoreactivity was detectable in mossy fibers. Each subspecies labeled different kinds of interneurons that were particularly numerous in, but not restricted to, the hilus. These data support the contention that different subtypes of hippocampal neurons are distinguished by the expression of different combinations of PKC subspecies under resting conditions.