bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuronal biosensors: A progress report
Authors: Leech Dónal , Rechnitz Garry A. 
Published: May 2005

AbstractA review of the progress of research in the development of intact chemoreceptor‐based biosensors is presented. These sensors utilize the chemosensing ability of the antennules of various decapod crustacea to sensitively and selectively detect chemical stimulants. Suction microelectrodes attached to the antennular nerve fibers are used to detect action potential firing upon binding of the stimulant to the receptor, allowing quantitation of the analyte. Recent developments in the use of different species and in improvements in experimental setup, data handling procedures, and sensor lifetimes are reported.
Anodic stripping voltammetry of copper in natural waters: A qualitative approach to the additional peak(s) occurrence
Authors: Boussemart Marc , Menargues Luc , Benaïm Jean‐Yves 
Published: May 2005

AbstractIn the presence of natural organic species, the electrochemical behavior of metals can be modified. Several authors have already noticed an extra peak or shoulder in the Cu peak during anodic stripping voltammetry (ASV) analysis, but the origin of this interference was generally not investigated and the experimental conditions were modified to make it disappear. In this article, this phenomenon alone was studied. The organic matter dissolved in interstitial waters of marine sediments was fractionated by ultrafiltration and gel permeation chromatography. The resulting fractions were qualitatively studied with respect to the complexity of the voltammograms they exhibit during an ASV analysis of Cu. Very similar electrochemical behaviors (multiple peaks) were found for interstitial waters and humic substances. The fractionation experiment suggests that particular families of molecules, which can be separated, are responsible for these extra peaks. Therefore, the “multipeak” phenomenon is related to the quality of the organic matter rather than to its quantity. This fact, supported by several experiments [DPASV, differential pulse polarography (DPP)], has led to a model which, although still somewhat speculative, describes well the usual observations: the extra peaks would originate from the oxidation of organic copper species [most likely as Cu(I)] adsorbed and stabilized on the mercury drop electrode.
Glassy carbon electrodes coated with electropolymerized resole prepolymer mixtures: Amperometric response to phenols and application as chromatographic sensors
Authors: Ortiz Patricia I. , Nader Paul R. Abu , Mottola Horacio A. 
Published: May 2005

AbstractResole mixtures made with phenol, 4‐hydroxybenzaldehyde, and 4‐hydroxybenzoate electrochemically generate films that protect glassy carbon surfaces from poisoning. The high oxygen content of these films mimics the surface characteristics of activated carbon electrodes and permits their continuous use for detection in flowing streams. The amperometric response of different phenolic materials at these chemically modified surfaces and their liquid chromatographic application as electrodes in thin‐layer cells are reported. Comparative considerations using a post‐column enzyme reactor and redox‐mediated electrochemical detection are also presented.
Cathodic stripping voltammetric measurements of cholesterol following adsorptive preconcentration at the static mercury drop electrode
Authors: Tuzhi Peng , Huiping Li , Rongshan Lu 
Published: May 2005

AbstractA new electrochemical method for direct measurement of cholesterol by cathodic stripping voltammetry is presented. The method is based on controlled adsorptive preconcentration at the static mercury drop electrode, followed by differential pulse voltammetric determination, in which adsorbed cholesterol reduces and shows stripping current at ca. −1.04 V (versus Ag/AgCl). The current was linear with the cholesterol concentration in the range of 0.2–8 μM. The detection limit found was 0.02 μM (10 minute preconcentration), and the relative standard deviation (at 0.6 μM level) 4.6%. Cyclic voltammetry was used to explore the adsorptive and electrochemical behavior. The adsorptive stripping response was evaluated with respect to preconcentration time, concentration dependence solution, stripping model, possible interference, and other variables. Applicability to serum analysis was illustrated.
In situ voltammetric measurements in natural waters: Future prospects and challenges
Authors: Tercier M.‐L. , Buffle J. 
Published: May 2005

AbstractThe state of the art and challenges in developing in situ voltammetric probes for direct measurements in natural waters are presented. Articles dealing with this topic are reviewed. Use of voltammetric probes in the laboratory and in the field is outlined. An up‐to‐date account of the results reported in the literature on the development of existing in situ voltammetric systems for such measurements is given. Emphasis is placed on the need for such systems to gain a better understanding of the mechanisms of processes occurring in natural aquatic systems. Suggestions are made for future development.
Digitally simulated predictions of the voltammetric current response relative to adsorbed enzyme‐modified electrodes
Authors: Randriamahazaka Hyacinthe , Nigretto Jean‐Maxime 
Published: May 2005

AbstractDigital simulation has been used to model the current response of an enzyme‐partially coated solid electrode. Enzymatic activities were detected using cyclic voltammetry by monitoring the release with time of a redox label split from a substrate contained in the solution. The predicted calibration curve indicated that, depending on the value of the catalytic rate constant, the different trends observed were controlled either by pure diffusion, by pure catalysis, or by a combination thereof. A procedure to attain the pertinent kinetic and diffusion properties affecting this system is given.
Determination of nitrite ions in well water by biamperometric standard addition
Authors: Lichtig Jaim , de Oliveira Rezende Maria Olímpia 
Published: May 2005

AbstractA new modified biamperometric method of analysis is proposed which has the advantage of producing straight lines as plots. Nitrite ions in well water have been determined by biamperometry and standard addition of solutions containing nitrite or iodate ions. Two platinum foils are immersed in the solution and 100 mV potential is applied between the electrodes; the resulting current is measured. The standard nitrite or iodate ions react with excess of iodide ions, producing triiodide. The reversible redox pair I/I−is responsible for a change in current, allowing the biamperometric measurement. The concentration of triiodide formed depends on the nitrite concentration. Twenty ppb of nitrite ions have been determined with good accuracy and precision. EDTA was added to eliminate interference from Fe(III), Cu(II), and other metal ions.
Applications of adsorptive stripping voltammetry in the determination of trace and ultratrace metals
Authors: Paneli Miropi G. , Voulgaropoulos Anastasios 
Published: May 2005

AbstractRecent advances in adsorptive stripping voltammetry (AdSV) are reviewed. The mechanisms of the adsorptive and stripping steps are given. The criteria of ligand selection, along with the present status and future trends in AdSV for trace element analysis, are discussed. Tables containing the elements determined by AdSV and the ligands used in AdSV, as well as the real samples analyzed and operational conditions, are presented (together with 171 references).
Monoalkylferrocene‐mediated amperometric enzyme electrodes for glucose determination
Authors: Razumas Valdemaras , Kulys Juozas , Knichel Martin , Wiemhöfer Hans‐Dieter , Göpel Wolfgang 
Published: May 2005

AbstractAmperometric biosensors for the determination of β‐D‐glucose are described. Glucose‐sensitive graphite electrodes are prepared by adsorptive immobilization of n‐butylferrocene (n‐BFc), ter‐butylferrocene (t‐BFc), or ethylferrocene (EFc). Glucose oxidase from Aspergillus niger is immobilized on the monoalkylferrocene‐modified surfaces of the graphite electrodes by covalent attachment. The biosensors based on n‐BFc, t‐BFc, and EFc could be used at potentials of 0.3, 0.325, and 0.275 V, respectively (vs. SCE reference electrode). A linear steady‐state current response, proportional to the glucose concentration in a range of 1–20 mM, is observed for the t‐BFc‐ and EFc‐mediated enzyme electrodes. Data are presented on the influence of potential, oxygen, pH, and temperature upon the electrodes. Results are discussed on the basis of the structural features of the mediators.
Studies on the voltammetric behavior of a bismuthiol I‐containing carbon paste electrode: Determination of traces of bismuth
Authors: Cai Xiaohua , Kalcher Kurt , Magee Robert J. 
Published: May 2005

AbstractThe voltammetric behavior of a bismuthiol I‐containing carbon paste electrode was studied. Bismuthiol 1 is electroactive, when mixed with carbon paste as an electrode modifier, and is oxidized at 0.3 V and re‐reduced at −0.6 V (vs. SCE). Nevertheless, it can be used as a modifier of carbon paste electrodes for the preconcentration and subsequent voltammetric measurement of bismuth, if suitable measurement conditions for the analysis are met. Bismuth(III) can be preconcentrated from acidic solutions onto this electrode under open circuit conditions. Linearity between current response and concentration can be achieved for 0.005 to 4 μg/ml bismuth using cathodic differential pulse voltammetry after preconcentration for 0.5 or 2 minutes. The interferences as well as various parameters for the preconcentration and measurement of bismuth(III) were investigated.
Optimization of conditions for mercury‐coated carbon fiber electrode formation and their influence on the cathodic stripping voltammetry of Se(IV)
Authors: McLaughlin Kieran , Rodriguez Jose Ramon Barreira , Garciá Augustin Costa , Blanco Paulino Tuñón , Smyth Malcolm R. 
Published: May 2005

AbstractThe conditions for the deposition of mercury on the surface of carbon fibers to permit the sensitive and reproducible voltammetry of Se(IV) have been investigated. Several procedures employing both predeposition and in situ formation of a mercury film on the carbon fiber were evaluated, and the effect of the mercury concentration and plating time upon the sensitivity of the stripping response for Se(IV) was determined. Due to the steady‐state diffusional mass transport characteristics exhibited by these electrodes, the need for stirred solutions, a specific deposition potential, and a deposition time period in the stripping voltammetric procedure was eliminated. This procedure gave rise to a linear response up to 3 ng/ml, a detection limit of 0.11 ng/ml, and a relative standard deviation (RSD) of 4.4% at 5 ng/ml (n = 5) for determination of Se(IV).
Macrocyclic oxamides as ionophores for lead‐selective membrane electrodes
Authors: Malinowska Elzbieta , Jurczak Janusz , Stankiewicz Tomasz 
Published: May 2005

AbstractA set of macrocyclic oxamides intended to be used as potential ionophores for lead ions in solvent polymeric membrane electrodes was investigated. The influence of the structure of ligands (number and distribution of oxygen donor atoms and ring size) on the selectivity was examined. Pronounced preference of lead over other divalent and some monovalent cations was observed for the 21‐membered‐ring oxadiamides (ionophores 1 and 7). These electrodes exhibited a linear response within the activity range of 10−5.4 −10−15 M in Pb(NO3)2 solutions.
Voltammetric determination of the antidepressant trimipramine at a lipid‐modified carbon paste electrode
Authors: Khodari Mahmoud 
Published: May 2005

AbstractThe voltammetric behavior of trimipramine at a carbon paste electrode (CPE) modified with some fatty acids is investigated. This hydrophobic drug is accumulated at the electrode by a combined adsorption/extraction process, with greatly enhanced response over the unmodified paste. The linearscan response was characterized with respect to preconcentration period, pH, paste composition, reproducibility, possible interferences, and other variables. The detection limit was found to be 1 × 10−9 M. The determination of trimipramine in urine required no pretreatment other than dilution with phosphate buffer and medium exchange technique.
A new application of fast green in catalytic analysis—catalytic determination of ultratrace ruthenium with oscillopolarographic detection
Authors: Zhiliang Jiang , Chen‐zhen Qin 
Published: May 2005

AbstractExperiments show that ruthenium [Ru(III)] has a very strong catalytic effect on the slow redox reaction between fast green (FG) and potassium periodate in hydrochloric acid medium, and that FG exhibits a sensitive single‐sweep oscillopolarographic wave at −0.56 V (versus SCE) in the pH 3.9 of acetate buffer solution. The oscillopolarographic behavior has been investigated. A novel, highly sensitive, and selective catalytic reaction‐oscillopolarographic method for Ru has been proposed according to the Ru(III) catalytic effect on the reaction. A detection limit of 0.27 ng/L and a calibration graph from 0.8 to 40 ng/L Ru were obtained by the fixed‐time procedure. Ruthenium in an ore sample was determined by this method with excellent results.
Study on the electrooxidation of biliverdin by in situ thin‐layer spectroelectrochemistry
Authors: Niu Jianjun , Dong Shaojun 
Published: May 2005

AbstractThe electrooxidation reaction of biliverdin (BV) is studied by in situ spectroelectrochemistry with rapid spectra scanning in an optically transparent thin‐layer cell. The study reveals that the oxidation process of BV is very complicated and involves many stages. The average formal potential of BV is obtained for the first time as E°′ = 0.634 V (vs. Ag/AgCl), and the electrooxidation mechanism of BV is proposed.
Controlled electrochemical preparation of enzymatic layers for the design of amperometric biosensors
Authors: Coche‐Guerente Liliane , Cosnier Serge , Innocent Christophe , Mailley Pascal , Moutet Jean‐Claude , Morélis Renée M. , Leca BÉAtrice , Coulet Pierre R. 
Published: May 2005

AbstractA newly synthesized pyrrole derivative was used for enzyme entrapment on carbon or platinum electrodes by electropolymerization. Three enzymes were tested: glucose oxidase (GOD), tyrosinase, and choline oxidase. Contrary to other techniques using electropolymerization in solution, a drop of enzyme‐monomer mixture was deposited and allowed to dry on the electrode surface before the electropolymerization. This procedure enables one to control the amount of entrapped enzyme and to easily obtain multilayer assemblies.
Self‐assembled lipid bilayers as a potassium sensor
Authors: Rehák Marián , Šnejdárková Maja , Otto Matthias 
Published: May 2005

AbstractThe effect of valinomycin on a novel bilayer lipid membrane (BLM) system supported on a metallic wire (s‐BLM) has been investigated. An increase in concentration of valinomycin from 6 × 10−6 to 6 × 10−4 mol L−1 increases the conductivity of the system after addition of potassium ions. A remarkable effect of the buffer medium on the electrode response has been observed, a solution of 0.1 M Tris‐HCl being most suitable. The assembled electrode system is stable for about 120 hours. A linear response toward potassium has been found in the range from 2.5 × 10−3 to 1.3 × 10−1 mol L−1. Effect of pH, temperature, and possibly interfering substances are reported.
Cyclic voltammetry of ferrocenecarboxylic acid monomolecular films and their reaction with glucose oxidase
Authors: Barmin Anatoli V. , Eremenko Arkadi V. , Kurochkin Ilya N. , Sokolovsky Andrei A. 
Published: May 2005

AbstractMonomolecular films of ferrocene derivatives (FD) and of glucose oxidase (GOD) have been formed on a graphite electrode by the Langmuir‐Schaefer (LS) method with the help of amphiphilic polymers. Cyclic voltammograms of these films and of their interaction with glucose oxidase were studied. Ferrocenecarboxylic acid, incorporated into polymeric matrices by adsorption to a monomolecular polymer film or by the direct mixing with a polymer solution before LB‐film formation, retain their mediator properties in the reaction with GOD. The amperometric response of a graphite electrode with immobilized multilayer films containing polymer matrices, ferrocenecarboxylic acid and GOD were linear over the range 1–20 mM of glucose.
Crown ethers in stripping voltammetry of palladium
Authors: Tsymbal Maria V. , Tuijan Iva Ya. , Temerdashev Zaual A. , Brainina Khjena Z. 
Published: May 2005

AbstractThe similarity in the structures (presence of hexatomic rings) of crown ethers and graphite is used for adsorptive modification of the graphite electrode surface. The effect is exploited in stripping voltammetry for the determination of palladium. Anodic currents observed at potentials of 0.6 to 0.65 V (vs. Ag/AgCI electrode) are the source of information about adsorption of the crown ethers. Maximum adsorption of the reagents takes place at potentials close to the potential of zero charge of graphite. Deposition of palladium on the electrode surface is enhanced, the closer the values of the diameters of the crown‐ether rings and Pd(II) are.
The influence of electrolyte media on the cathodic stripping voltammetry of lead dioxide on glassy carbon electrode
Authors: Velayutham D. , Noel M. 
Published: May 2005

AbstractThe influence of three electrolyte media, namely, acetate buffer, nitric acid, and perchloric acid, on cathodic stripping of lead dioxide at a glassy carbon electrode (GCE) was studied using cyclic voltammetry (CV) and linear sweep stripping voltammetry (LSSV) techniques. One M acetic acid/1 M sodium acetate, 0.1 M nitric acid, and 0.1 M perchloric acid were found to give a sharp cathodic stripping voltammetric (CSV) response. Various factors, such as concentration of supporting electrolyte, depositior, potential (Edep) deposition time (tdep), and concentration of Pb2+ (C), are also presented and discussed. The lowest detection limit of Pb2+ in acetate buffer is 5 × 10−8 M and, in 0.1 M nitric acid and 0.1 M perchloric acid, is 1 × 10−5 M. The influence of medium on cathodic stripping peak broadening is analyzed in detail. It is concluded that the formation of insoluble intermed ates is the major cause for peak broadening, and the ability of the supporting electrolyte anion to inhibit the formation of such intermediates, through complexation, is the major reason for sharper stripping voltammetry response.
Determination of lead in microliter amounts of whole blood by stripping potentiometry
Authors: Jagner Daniel , Renman Lars , Wang Yudong 
Published: May 2005

AbstractLead in whole blood is determined using a commercial potentiometric stripping analyzer in combination with a portable personal computer and a new electrode design permitting rotation of the sample. A 70 μL blood sample is added to 200 μL distilled water contained in a disposable test tube. After mixing, 400 μL of a matrix‐modifying solution containing hydrochloric acid, mercury (II) ions, Triton X‐100, and bismuth (III) as an internal standard, is added to the sample which is then transferred to the sample holder. Lead amalgam is deposited on the glassy carbon electrode by means of a pulsed potential cycle for 3 minutes after which lead is reoxidized by means of a constant current. The complete electroanalytical procedure, including result evaluation by means of the internal standard, and graphical display is under computer control. For ca. every 15th sample, the instrument is recalibrated, if necessary, using two whole blood standards. The relative precision is ca. 10% and the detection limit 3.5 μg/L. The stripping potentiometry results agree well with the results obtained by inductively coupled plasma mass spectrometry in the analysis of whole blood from individuals occupationally exposed to lead and with the results obtained by graphite‐furnace atomic spectroscopy in the analysis of whole blood from 141 school children.
Kinetic studies on membraneless amperometric biosensors prepared from xanthine oxidase, organic conducting salt, and silicone oil
Authors: Korell Ulrich , Spichiger Ursula E. 
Published: May 2005

AbstractMembrane‐free amperometric biosensors have been prepared from xanthine oxidase powder (XOD) (E.C.1.2.3.2) the organic conducting salt TF‐TCNQ, and silicone oil The sensor response to hypoxanthine can be described by the ezyme‐kinetic Michaelis‐Menten formalism with good correlation over a wide range of potential (–100 tc +300 mV vs Ag/AgCl) and pH (6.10 to 8.80)values. Measurements with rotating disk rotating disk electrodes reveal that XOD is oxidized by at least two transfer to the mediators so that the sensor can be operated in air‐saturated solution. Since open circuit conditions alter the kinetic parameters of the sensor, operation in flow analysis systems is recommended. Analytical features including response time (t95 ≈ 10 seconds), detection limit (ca. 10 nM hypoxanthine), selective over interferents (e.g., ascirbate), and simplicity of preparation as well as operation and storage stability compare very favorably with other OXD biosensors.
Effect of electrochemical pretreatment on protein adsorption at glassy carbon electrodes protein
Authors: Downard Alison J. , Roddick Alisa D. 
Published: May 2005

AbstractThree types of electrochemical, pretreatments (ECPs) were assessed as a means of reducing albumin adsorption at glassy carbon electrodes. The cyclic voltammetric and differential pulse responses of the probe analyte, ferrocenemonocarboxylic acid (FCA), in the absence and presence of 4 g L−1 bovine serum albumin (BSA) were used to monitor protein adsorption at pretreated electrodes. Severe dc pretreatment in acid increased BSA adsorption (compared to that at a polished electrode), whereas square‐wave pretreatment in aqueous NaCl and dc pretreatment in base both reduced the amount of BSA adsorption. The effects of the latter two ECPs on the response of acetaminophen in the presence of BSA were examined. The loss of sensitivity in the presence of BSA was reduced at electrodes which were pretreated. However, our results sugges: that ECP which leads to very strong accumulation of analyte may have a deleterious effect on electrode performance in the presence of protein.
Permeation of solutes through an electropolymerized ultrathin poly‐o‐phenylenediamine film used as an enzyme‐entrapping membrane
Authors: Centonze Diego , Malitesta Cosimino , Palmisano Francesco , Zambonin Pier Giorgio 
Published: May 2005

AbstractPermeation of electroactive organic probes through an electroinactive and passivating poly‐o‐phenylenediamine (PPD) film electropolymerized on Pt and glassy carbon (GC) electrodes has been investigated by cyclic and rotating disk electrode (RDE) voltammetry. The access of solutes to the metal‐polymer interface appears mainly governed by specific chemical interactions, influencing partition, and diffusion phenomena, rather than by exclusion effects based on molecular size or charge. Potential cycling of the film induces fine modifications in the chemical/physical structure of the polymer, as evidenced by electron spectroscopy for chemical analysis (ESCA) measurements and by an enhanced permeation of certain solutes. The membrane is, however, stable in the pH and potential range usually employed in its application, that is, as an enzyme‐entrapping membrane in amperometric biosensors; because of membrane permselectivity, the electrochemical response of the most common electroactive interferents is deeply depressed.