bluuebunny/crossref_metadata_2025_split huggingface dataset:
The properties and applications of amperometric gas sensors
Authors: Cao Zhuang , Buttner William J. , Stetter Joseph R. 
Published: May 2005

AbstractThe properties and applications of amperometric gas sensors are reviewed. An introductory discussion of the general mechanism of electrochemical gas reactions and an outline of the construction of amperometric gas sensors is presented. The performance of sensors and the relationship of the sensor's performance to the materials of construction and sensor components are described. The analytical characteristics of a sensor such as sensitivity, selectivity, response time and noise are intimately related to the materials chosen for membranes, conductive electrolytes, and active electrocatalysts, as well as the choice of effective operating conditions. The applications of amperometric gas sensors to specific analytical problems are discussed in the context of required performance. Finally, this article points out technical gaps and the future direction of amperometric gas sensor research including some potential applications. References that are relevant to the field of amperometric gas sensors are summarized in a table which contains the author's name, the electrochemical reaction, and an exemplary application.
The EC′ mechanism: Split waves at the channel electrode
Authors: Fisher Adrian C. , Compton Richard G. 
Published: May 2005

AbstractA computational strategy is presented for the simulation of current‐voltage curves of electrode processes with very fast coupled homogeneous kinetics at the channel electrode. The approach is illustrated by consideration of the EC′ mechanism that relates to the homogeneous catalysis of electrochemical reactions. It is shown that for fast catalytic reactions “split” voltammetric waves are observed where the two components of the wave result first from the direct reduction (oxidation) of a mediator and, secondly, to a prewave in which mediated reduction of a substrate takes place.
A square‐wave voltammetry in a cathodic stripping mode
Authors: Lovrić Milivoj , Pižeta Ivančica , Komorsky‐Lovrić Šebojka 
Published: May 2005

AbstractA model of cathodic stripping square‐wave voltammetry (SWV) of insoluble mercuric salt accumulated at the mercury drop electrode surface is developed. Theoretical relationships between the properties of responses and the parameters of both the redox reaction and the SWV signal are analyzed. Both reversible and quasireversible redox reactions are considered. The nature of quasireversible maximum is discussed. Numerical simulations are compared qualitatively with the SW stripping voltammograms of electrodeposited HgS.
Column Liquid Chromatography in combination with immobilized enzymes and electrochemical detection and its applications in some industrial processes
Authors: Marko‐Varga György A. 
Published: May 2005

AbstractThe first part of the paper provides a review of the pre‐ and postcolumn derivatization systems used in Column Liquid Chromatography (CLC) in combination with immobilized enzyme reactors (IMERs) and electrochemical detection (EC). In the second part, an outline of important factors to consider in the optimization of CLC‐IMER‐EC systems are presented. Three industrial applications are described utilizing enzyme‐based detection or enzymes for sample handling purposes. In two of the cases, CLC‐IMER were used in combination with amperometric detection using chemically modified electrodes (CME). These applications were performed in our laboratory, and the high selectivity and sensitivity of these systems as well as the problems encountered in these complex samples will be discussed.
Capillary electrophoresis—electrochemistry of microdialysis samples for pharmacokinetic studies
Authors: O'Shea T. J. , Telting‐Diaz M. W. , Lunte S. M. , Lunte C. E. , Smyth M. R. 
Published: May 2005

AbstractElectrochemical detection has been shown to be a sensitive method of detection in capillary electrophoresis (CE). The small sample volume required for CE makes it ideal for the analysis of microdialysis samples. In this paper, capillary electrophoresis with electrochemical detection is utilized in the analysis of samples obtained during continuous monitoring of the pharmacokinetics of L‐dopa in the rat. The detection limit for L‐dopa was 98 attomoles or 3.9 ng/mL. The elimination half‐life was calculated to be 10.3 ± 1.1 minutes. Voltammetric characterization was used to verify the identity of L‐dopa and its metabolites. The effects of electrochemical pretreatment on the detector performance was also investigated.
Analysis of salbutamol in human plasma by high‐performance liquid chromatography with electrochemical detection using a micro‐electrochemical flow cell
Authors: Sagar Kamal A. , Hua Chi , Kelly Mary T. , Smyth Malcolm R. 
Published: May 2005

AbstractA high‐performance liquid chromatographic (HPLC) method for the determination of salbutamol in human plasma is described based on separation on a reversed‐phase C18 column followed by detection using a carbon fiber‐based electrochemical detector. The carbon fiber‐based flow electrode used in the analytical system showed some advantages over conventional electrochemical detectors using glassy carbon electrodes. It is easy to prepare, flexible to operate, and suffers less trouble from air bubbles and leaks. It was shown that this kind of microelectrode flow detector exhibits a better detection limit (1 ngml−1) to that obtained using a conventional glassy carbon electrode flow detector (3 ngml−1). The method was found to be reproducible, with a mean overall coefficient of variation (C.V.) of 5.4%, and drug recovery was in excess of 85% at the concentration levels studied.
A reticulated vitreous carbon spectroelectrochemical detector for flow injection analysis and liquid chromatography
Authors: Sorrels Janet Weiss , Dewald Howard D. 
Published: May 2005

AbstractA spectroelectrochemical detector for flow injection and liquid chromatography is described. The detector design has dimensions of a standard 1 cm sample cuvette with a replaceable reticulated vitreous carbon working electrode. No special cell holder or modifications to the spectrophotometer are required to use the detector. Chronocoulometry is used to indicate a trend from thin‐layer behavior toward semi‐infinite diffusion behavior as the electrode pore size increases. Ferro‐/ferricyanide solutions were used to evaluate the flow injection characteristics of the detector. A sampling rate of 180 injections per hour was used. Linear calibration curves in the micromolar range were achieved with a reproducibility of 2–7%. A mixture of phenol, chlorophenols, and nitrophenols was used to investigated the simultaneous electrochemical and optical response for liquid chromatography.
Determination of 2‐thiothiazolidine‐4‐carboxylic acid in urine by liquid chromatography with electrochemical detection
Authors: Ciucu Anton , Baldwin Richard P. 
Published: May 2005

AbstractAn assay procedure utilizing liquid chromatography and amperometric detection at a chemically modified electrode (CME) has been developed for the determination of 2‐thiothiazolidine‐4‐carboxylic acid (TTCA) in urine samples. The electrocatalytic activity of the CME, which consisted of a glassy carbon surface coated with an electropolymerized cobalt phthalocyanine film, permitted optimum response at a potential of +0.75 V vs. Ag/AgCl with a detection limit of 7 pmol for TTCA and with no sample preparation required. In case of fouling of the electrode surface by sample constituents, the polymeric cobalt phthalocyanine electrode surface could be renewed with a variability of less than 10% and an equilibration time of less than 15 minutes.
Multienzyme containing tissue‐based and ferrocene‐mediated bioelectrode for the determination of polyamines
Authors: Lin Meng Shan , Hare Minoru , Rechnitz Garry A. 
Published: May 2005

AbstractOat seedling tissue and ferrocene/ferricinium were coimmobilized in a carbon paste matrix to construct a biosensor for polyamines. The oat tissue is rich in the enzymes polyamine oxidase and peroxidase while the mediator facilitates electron transfer between the electrode and hydrogen peroxide. The determination of the polyamines spermine and spermidine, in both batch and flow injection modes, was evaluated. The concentration of polyamine was monitored through hydrogen peroxide in the presence of oxygen as cosubstrate of polyamine oxidase. A reductive potential of 0.0 V was chosen for monitoring ferricinium which is generated by peroxidase. The detection limit (S/N = 3) for spermidine and spermine in the batch system was 0.19 and 1.15 μM, respectively. The relative standard deviation for twelve replicate analyses of 10 μM spermidine was 4.5%. The activity of the tissue modified carbon paste electrode decreased to 45% of the original value after a storage for 8 days in buffer solution at 4°C.
Crown ether derivatives of anthraquinone as ionophores in ion‐selective electrodes
Authors: Allen John R. , Cynkowski Tadeusz , Desai Jayant , Bachas Leonidas G. 
Published: May 2005

Abstract1,8‐anthraquinono‐18‐crown‐6 and 10‐[(2,4‐dinitrophenyl)azo]‐9‐hydroxy‐1,8‐anthraceno‐18‐crown‐6 were prepared from 1, 8‐dichloroanthraquinone and used in the development of ion‐selective electrodes. The electrodes based on 10‐[(2,4‐dinitrophenyl)azo]‐9‐hydroxy‐1,8‐anthraceno‐18‐crown‐6 displayed better selectivity for potassium over sodium and had fewer interferences. The differences and similarities between the ionophores, as well as the optimum conditions for the preparation of the electrodes are discussed.
Influence of methyl group on the differential pulse polarographic activity of guanosine
Authors: Kamal M. M. 
Published: May 2005

AbstractThe polarographic activity of guanosine, 1‐methylguanosine, 2‐methylguanosine, and 7‐methylguanosine was investigated over a wide pH range by using differential pulse polarography. It was found that only 7‐methylguanosine exhibits a well‐developed reduction peak, whereas the other compounds are apparently polarographically inactive. The polarographic response of 7‐methylguanosine results from the attachment of the methyl group at N7 of the imidazole ring, which facilitates the reduction process at the N7C8 center. The dependence of the reduction peak on the various experimental conditions is considered. 7‐Methylguanosine can be determined over the concentration range of 2–10 μM.
Indirect determination of cesium in brine by single‐sweep oscillopolarography
Authors: Dan Dezhong , Du Gu , Wan Yuping 
Published: May 2005

AbstractA new method for indirect determination of cesium by single‐sweep oscillopolarography is presented. The method is based on the quantitative precipitation of cesium with tetraiodobismuthate(III) ion (BiI); the BiI ion can yield a well‐defined polarographic derivative wave at −0.24 V (vs. SCE) in acetic acid solution. The linear range for cesium was dependent on Bil concentration. The detection limit was 10 μg. The procedure is simple, rapid, and convenient, and has been used to determine cesium in brine after extraction with large granular ammonium phosphomolybdate and BAMBP. The polarographic behavior and mechanism of reduction are investigated. The redox process appears to be irreversible and controlled by diffusion with adsorptive characteristics.
Some observations on the accumulation potential in adsorptive stripping voltammetry
Authors: Li Chiang , James Bruce D. , Magee Robert J. 
Published: May 2005

AbstractA newly named parameter, “initial scan potential”, the potential from which the voltammetric scan starts rather than the widely accepted accumulation potential, has been found to be responsible for some of the important features of voltammograms obtained in the adsorptive stripping voltammetry (AdSV) of some organochlorine compounds (DDT, Dieldrin, 2,4‐ dichlorophenoxyacetic acid, 2,4,5‐trichlorophenoxyacetic acid). The experimental evidence reported strongly confirms the nonfaradaic nature of the preconcentration step in adsorptive stripping voltammetry.
Monte Carlo simulation of diffusional noise at microelectrodes
Authors: Borkowski Marcin , Stojek Zbigniew 
Published: May 2005

AbstractThe Fick's diffusion laws, which employ continuous concentration functions, may be at their limit when a combination of a microelectrode and a very short experimental time is used. This situation became a reality when the applied scan rates reached the level of MV/s. So, a model based on random motions of particles, and thus belonging to Monte Carlo methods, was developed to enable constructing theoretical electroanalytical curves loaded with expected diffusional noise. The obtained theoretical curves indicate that the diffusional noise may increase dramatically when a very small electrode size and a very short pulse time or a very high sweep rate are employed. For high concentrations, the model becomes equivalent to the Finite Difference scheme. Partial verification of the theory is possible, as smoothing of the theoretical “noisy” curves should produce the signals predicted by the known analytical solutions.
Conductance studies with use of an oscillometric detector
Authors: Pungor Ernö , Pál Ference , Slezsák István , Hrabéczy Andrea 
Published: May 2005

AbstractBy comparing calculated and experimental data, the accuracy of the assumed equivalent circuit of the oscillometric microcell was proved. The cell parameters were defined and can be used to characterize the cell and to establish the range of its applicability. The correlation between the output voltage of the oscillator and the sample concentration was studied in the case of the measuring principle applied (measurement of quality factor Q). A relationship was derived for describing the dependence of the analytical signal on the concentration, which enabled the factors influencing the sensitivity to be determined. All these studies served to optimize the cell geometry and oscillator circuit.
Automatic mercury drop electrode with double solenoid activated valve
Authors: Pedrotti Jairo , Angnes Lucio , Gutz Ivano G. R. 
Published: May 2005

AbstractThe construction and evaluation of a simple, low cost, and versatile automatic mercury electrode, working as dropping (DME), hanging (HMDE), or static drop electrode (SMDE), is described. Fast action of the needle valve is obtained with two solenoids, one for opening the valve and the other for closing it. The electrode can be controlled from a microcomputer or with a digital circuit. The performance of this electrode compares favorably with that of commercial ones in terms of area reproducibility (std. dev. < 0.05%), response time of the valve, current profile during potentiostatic extrusion of the drop, and flexibility of use.
Use of ion exchangers for the voltammetric determination of NTA and EDTA in natural waters
Authors: Voulgaropoulos Anastasios , Tzivanakis Nicolaos 
Published: May 2005

AbstractThe indirect trace determination of NTA and EDTA in natural waters is carried out by differential pulse anodic stripping voltammetry (DPASV), after their complexation with bismuth(III). Chloride ions in relatively high concentrations as well as iron(III) and copper(II) interfere with the determination of EDTA and NTA in natural waters. These interferences can be removed by using ion exchangers in the pretreatment of the sample before the voltammetric determination. The interferences of phosphonic acids and humic acids can also be negated. The determination was performed in sea, lake, river, rain, and waste waters.
Binding capacity of casein to lead and voltammetric speciation of lead in milk with a nafion coated electrode
Authors: Vidal Juan C. , Viñao Rosa B. , Castillo Juan R. 
Published: May 2005

AbstractThe complexation of lead with casein (CS) was studied by several voltammetric methods, as was the selective determination and speciation of lead in milk. First, cyclic voltammetry (CV) was used to examine the influence of adsorbed casein and complexation on the electrochemical response of lead at neutral and alkaline pHs. Second, by titrating solutions of CS with lead, two mathematical methods based on differential‐pulse anodic stripping voltammetry (DPASV) for evaluating the binding properties of CS to lead were compared with a hanging mercury drop electrode (HMDE) and a Nafion‐covered mercury film electrode (Nf‐MFE). In all cases, the conditional stability constants for the Pb‐CS complex agreed well and were close to log β′ = 5.5 at pH 7.0. Finally, lead was directly determined with the chemically modified electrode in acidified samples (≈︁pH 0.3) of whole and skim milk at the ng/ml level, with no need for preliminary acid digestion.
The mathematical modelling of ionic diffusion through stagnant layers: A modification of the Morf and Simon equation
Authors: Lucas Sam , Desai Mohamed , Vadgama Pankaj 
Published: May 2005

AbstractAn improved mathematical model of dynamic responses of a glass pH electrode and its correlation with that of a membrane‐mounted glass pH electrode on the basis of HCl diffusion through the stagnant layer is reported here. The application of such a model and its validity to aqueous and gel films, such as porcine gastric mucus, is evaluated across the pH spectrum. Dynamic responses of the membrane‐mounted glass pH electrode, modelled on this basis gave an excellent fit to the experimental data across the pH range for both films. The modified model described here takes into account the presence of any effect at the membrane/mucus interface for the experimental set‐up. The technique and model thus enables determination of ion flux in mucus or any coated ion selective electrode.
Synergic effect of fulvic acids on the differential pulse adsorptive voltammetry of the Mo(VI)‐phenanthroline complex
Authors: Quentel François , Elleouet Catherine , Madec Christian 
Published: May 2005

AbstractIn acidic chloride media (pH 2), a chelate of Mo(VI) with 1, 10‐phenanthroline is adsorbed on a hanging mercury drop electrode and reduced at −0.575 V. In presence of fulvic acids, the signal is strongly enhanced owing to the formation of a mixed complex which is more readily adsorbed. The effect of various operational parameters (pH, ligand, and molybdenum concentrations, potential and time collection) on the response is discussed, and a sensitive adsorptive voltammetric procedure is developed.
Simultaneous polarographic chemometric trace analysis of pyrazine and its methyl derivatives
Authors: Yongnian Ni , Kokot Serge , Selby Mark , Hodgkinson Mark 
Published: May 2005

AbstractThe polarograms of mixtures of the cocoa flavor compounds, pyrazines, consist of overlapping peaks. This generally precludes the direct analysis of these compunds without prior separation. In this paper, polarographic conditions for the analysis of up to four component mixtures of pyrazines present at trace levels (150 ppb‐1 ppm) were investigated using differential pulse polarography (DPP) at a static mercury drop electrode (SMDE). A series of pyrazine mixtures were analyzed at pH 4.8 (phosphate/citric acid buffer) and the results were interpreted using partial least squares (PLS), principal component regression (PCR), and multiple linear regression (MLR) chemometric routines. In each case an orthogonally designed training set was used to facilitate predictions. The PLS and the PCR models produced acceptable results with recoveries, in general, being in the 97–104% range and RSD in the 4–10% range depending on the nature and complexity of the mixture analyzed.
Electrochemical reduction behavior and determination of nicoumalone
Authors: Reddy C. Suresh , Reddy S. Jayarama 
Published: May 2005

AbstractThe electrochemical reduction behavior of nicoumalone has been studied by using dc polarography, cyclic voltammetry, ac polarography, differential pulse polarography, millicoulometry, and controlled potential electrolysis in universal buffers ranging from pH 2.0 to 12.0 in DMF—water mixtures. Kinetic parameters such as diffusion coefficient (D) and forward rate constant (k) values are evaluated and a reduction mechanism is proposed. A simple and rapid differential pulse polarographic method has been developed for the determination of nicoumalone in pharmaceutical formulations using the standard addition method. The detection limit is 2.7 ng mL−1.
Direct electron transfer reaction of a blue protein from Alcaligenes faecalis strain 6
Authors: Iwasaki Yuzuru , Suzuki Masayasu , Takeuchi Toshifumi , Tamiya Eiichi , Karube Isao , Nishiyama Makoto , Horinouchi Sueharu , Beppu Teruhiko , Kadoi Hideo , Uchiyama Shunichi , Suzuki Schuichi 
Published: May 2005

AbstractThe direct election tranfer reaction of a copper‐containing blue protein from Alcaligenes faecalis strain 6 (AfBP) was investigated. AfBP showed quasi‐reversible electron transfer kinetics at an edge‐plane—oriented pyrolytic graphite electrode (PGE) without any electrode modifier. Investigation of the effect of solution conditions on the reaction suggested that a weak electrostatic interaction between the electrode and the protein facilitates the electron transfer.
Electrocatalysis of nitrite reductase fromAlcaligenes faecalisstrain 6 mediated by native redox partner
Authors: Iwasaki Yuzuru , Takeuchi Toshifumi , Tamiya Eiichi , Karube Isao , Nishiyama Makoto , Horinouchi Sueharu , Beppu Teruhiko , Kadoi Hideo , Uchiyama Shunichi , Suzuki Shuichi , Suzuki Masayasu 
Published: May 2005

AbstractA protein‐mediated electrocatalytic reaction is described. A blue protein fromAlcaligenes faecalisstrain 6 (AfBP) was used as a redox mediator for a nitrite reductase (NIR) from the same organism. Two steps of a homogeneous chemical reaction (AfBP‐NIR and NIR‐substrate), following the direct electron transfer reaction of AfBP (E C′C′), were analyzed, and the bimolecular rate constant of 1.8 × 106M−1·S−1for the AfBP‐NIR reaction was calculated from electrocatalytic current in cyclic voltammetry. The kinetic relation of the first and the second homogeneous reaction was discussed.
New amperometric biosensor for citrate with mercury film electrode
Authors: Hikima Satoshi , Hasebe Kiyoshi , Taga Mitsuhiko 
Published: May 2005

AbstractWe describe a new amperometric biosensor which is constructed from a mercury film electrode and an enzyme‐immobilized membrane. This biosensor is based on detecting the reduction current of an organic acid produced by enzyme reactions. The detection range of this biosensor was 5.0 × 10−4 – 3.0 × 10−3 M and relative standard deviation, R.S.D. at 1.0 × 10−3 M was 4.8%.
Electroanalytical determination of lormetazepam in pharmaceutical preparations and human urine
Authors: Zapardiel A. , Bermejo E. , Pérez López J. A. , Mateo P. , Hernández L. 
Published: May 2005

AbstractThe electrochemical properties of the drug lormetazepam have been studied at the mercury electrode. A method for determination of the drug in commercial preparations by differential pulse polarography has been devised, with mean relative errors lower than 1.4% and relative standard deviations lower than 3.3%. Controlled adsorptive accumulation of lormetazepam at a hanging mercury drop electrode (HMDE) provided the basis for its determination by stripping voltammetry at nanomolar concentration levels. The adsorptive stripping response was evaluated with respect to experimental conditions and parameters such as electrolyte, pH, accumulation potential, accumulation, time and concentration. A drug determination method for use in urine with previous extraction (98% recovery) has been developed, with a detection limit of 23 ngm·1−1 (40 second accumulation time) and a relative standard deviation around 6.8%.
Lettuce seed meal tissue‐based membrane electrode with high biocatalytic activity for hydrogen peroxide
Authors: Fang Yao , Cai Ronghui , Deng Jiaqi , Deng Zifeng 
Published: May 2005

AbstractA newly developed hydrogen peroxide selective membrane electrode using lettuce seed meal as source biocatalyst is described. This amperometric‐based probe exhibits high biocatalytic activity, long lifetime and favorable selectivity for the measurement of hydrogen peroxide.