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M. Julia Arcos - One of the best experts on this subject based on the ideXlab platform.

  • Simultaneous determination of chromium(VI) and chromium(III) at trace levels by Adsorptive Stripping Voltammetry
    Analytica Chimica Acta, 2002
    Co-Authors: Olga Domínguez, M. Julia Arcos
    Abstract:

    A new methodology was proposed for the speciation of chromium by differential pulse Adsorptive Stripping Voltammetry (DPAdSV) using pyrocatechol violet (PCV) and N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA) as complexing agents. In this procedure, a partial least squares (PLS) regression was used for the resolution of the strongly overlapping voltammetric signals from mixtures of Cr(III) and Cr(VI) in the presence of PCV and HEDTA. The relative error in absolute value was

  • Optimization of the experimental parameters in the determination of rifamycin SV by Adsorptive Stripping Voltammetry
    Analytica Chimica Acta, 2000
    Co-Authors: M. Asunción Alonso, S. Sanllorente, Luis A. Sarabia, M. Julia Arcos
    Abstract:

    Abstract A procedure for the determination of rifamycin SV by Adsorptive Stripping Voltammetry (AdSV) has been optimized. Two different voltammetric techniques, namely differential pulse Adsorptive Stripping Voltammetry (DPAdSV) and square wave Adsorptive Stripping Voltammetry (SWAdSV) were used. In order to determine the most sensitive technique, an optimization of the experimental parameters was carried out for every technique using experimental design methodology. A canonical analysis of the response surface was carried out, which was adjusted to determine the optimum and the influence of the experimental factors. When this lay outside the ambit of the experiment, the optimum path method was used for the optimising process. The detection limits obtained, 3.108 × 10 −8  mol dm −3 for DPAdSV and 1.233 × 10 −8  mol dm −3 for SWAdSV, show that SWAdSV is a more sensitive technique for the analysis of rifamycin SV. Finally, this method was used to determine rifamycin SV in real samples.

  • Optimization of digestion procedure for the determination of nickel in wine by differential-pulse Adsorptive Stripping Voltammetry
    The Analyst, 1998
    Co-Authors: S. Sanllorente, M. Julia Arcos
    Abstract:

    A method for the determination of nickel in wine by differential-pulse Adsorptive Stripping Voltammetry using dimethylglyoxime as complexing agent was optimised using experimental design methodology. In order to destroy organic matter, two different methods of treating the sample were considered. The UV irradiation method was selected and optimised for a smaller degree of uncertainty. The recovery factor obtained with five replicates was 1.02 ± 0.05.

  • Application of an optimization procedure in Adsorptive Stripping Voltammetry to the determination of nickel with DMG
    Electroanalysis, 1996
    Co-Authors: S. Sanllorente, M. Cruz Ortiz, M. Julia Arcos, Jesús López-palacios
    Abstract:

    A procedure for the determination of nickel by Adsorptive Stripping Voltammetry (AdSV), using dimethylglyoxime as complexing agent, has been optimized. The determination was carried out by two different techniques: differential pulse Adsorptive Stripping Voltammetry (DPAdSV) and square wave Adsorptive Stripping Voltammetry (SWAdSV). The selection of the experimental parameters was done using a factorial design which allows one to find the most significant variables, i.e., those which exert the greatest influence on the measured magnitude, with a reduced number of experiments. Posterior optimization of these variables provided the most adequate experimental conditions and it was under these conditions that the calibrations were made, using a robust regression method which allows the elimination of anomalous points.

M. Julia Arcos Martínez - One of the best experts on this subject based on the ideXlab platform.

  • Determination of oxcarbazepine by Square Wave Adsorptive Stripping Voltammetry in pharmaceutical preparations
    Journal of pharmaceutical and biomedical analysis, 2006
    Co-Authors: M. Encarnación Burgoa Calvo, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    Abstract A procedure for the determination of oxcarbazepine (OXC) by Square Wave Adsorptive Stripping Voltammetry (SWAdSV) has been optimized. Selection of the experimental parameters was made using experimental design methodology. The detection limit was 1.74 × 10 −7  mol dm −3 . This method was used to determine oxcarbazepine in pharmaceutical preparations.

  • Speciation of Antimony by Adsorptive Stripping Voltammetry Using Pyrogallol Red
    Electroanalysis, 2006
    Co-Authors: M. Jesús Gómez González, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    This paper proposes a procedure for the speciation of antimony by Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV) using pyrogallol red (PGR) as a complexing agent. It employs a Partial Least Squares regression (PLS) in the resolution of strongly overlapping voltammetric signals obtained from mixtures of Sb(III) and Sb(V) in the presence of pyrogallol red. The absolute value of the relative error was less than 3.5% when concentrations of several mixtures were calculated, the minimum concentrations being 9.98×10−9 mol dm−3 and 4.87×10−8 mol dm−3 for Sb(III) and Sb(V), respectively. Any undue effects caused by the presence of foreign ions in the solution were also analyzed. The procedure was successfully applied to the speciation of antimony in pharmaceutical preparations.

  • Optimization of the experimental parameters in the determination of lamotrigine by Adsorptive Stripping Voltammetry
    Analytica Chimica Acta, 2005
    Co-Authors: M. Encarnación Burgoa Calvo, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    Abstract This paper describes a procedure that has been optimized for the determination of lamotrigine (LTG) by Adsorptive Stripping Voltammetry (AdSV). Two different voltammetric techniques, namely differential pulse Adsorptive Stripping Voltammetry (DPAdSV) and square wave Adsorptive Stripping Voltammetry (SWAdSV) were used. In order to determine the most sensitive technique, optimization of the experimental parameters using experimental design methodology was carried out for each technique. The detection limits obtained, 4.68 × 10 −9  mol dm −3 for DPAdSV and 5.02 × 10 −9  mol dm −3 for SWAdSV, show that both techniques are almost the same sensitive for the analysis of lamotrigine. Finally, this method was used to determine lamotrigine in pharmaceutical preparations and in spiked human plasma samples.

  • Determination of gallium by Adsorptive Stripping Voltammetry.
    Talanta, 2004
    Co-Authors: M. Jesús Gómez González, Olga Domínguez Renedo, M. Asunción Alonso Lomillo, M. Julia Arcos Martínez
    Abstract:

    A procedure for the determination of gallium by differential pulse Adsorptive Stripping Voltammetry (DPADSV), using different complexing agents (ammonium pyrrolidine dithiocarbamate (APDC), pyrocatechol violet (PCV) and diethyldithiocarbamate (DDTC)), has been optimized. The selection of the experimental conditions was made using experimental design methodology. Under these conditions, the calibration was made and the detection limit was determined for each gallium-ligand complex. A robust regression method was applied which allowed the elimination of anomalous points. The detection limit, with alpha=beta=0.05, for gallium-APDC complex was 5.0x10(-8)moldm(-3), for gallium-PCV complex was 9.9x10(-9)moldm(-3), and the lowest detection limit (1.3x10(-9)moldm(-3)) was obtained with DDTC. For this reason, DDTC was selected for the determination of the gallium concentration in a certificate sample and in a spiked tap water sample. The linear dynamic range for gallium-APDC complex was from 5.0x10(-8) to 2.7x10(-7)moldm(-3), for gallium-PCV complex was from 5.0x10(-9) to 4.8x10(-7)moldm(-3), and for gallium-DDTC complex was from 1.0x10(-9) to 2.1x10(-7)moldm(-3).

  • Simultaneous Determination of Chromium(VI) and Aluminum(III) by Adsorptive Stripping Voltammetry with Pyrocatechol Violet
    Helvetica Chimica Acta, 2003
    Co-Authors: Miguel Cámara Vargas, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    A new methodology is presented for the simultaneous determination of chromium(VI) and aluminum(III) by differential-pulse Adsorptive Stripping Voltammetry (DPAdSV) with Pyrocatechol Violet (PCV) as a complexing agent. In this procedure, a partial least-squares regression (PLS) is used for the resolution of the strongly overlapping voltammetric signals from mixtures of CrVI and AlIII in the presence of PCV. The procedure was successfully applied to the determination of these metals in river water.

Richard G. Compton - One of the best experts on this subject based on the ideXlab platform.

  • Optimising carbon electrode materials for Adsorptive Stripping Voltammetry
    Applied Materials Today, 2017
    Co-Authors: Korbua Chaisiwamongkhol, Christopher Batchelor-mcauley, Stanislav V. Sokolov, Jennifer Holter, Neil P. Young, Richard G. Compton
    Abstract:

    Abstract Different types of carbon electrode materials for Adsorptive Stripping Voltammetry are studied through the use of cyclic Voltammetry. Capsaicin is utilised as a model compound for Adsorptive Stripping Voltammetry using unmodified and modified basal plane pyrolytic graphite (BPPG) electrodes modified with multi-walled carbon nanotubes, carbon black or graphene nanoplatelets, screen printed carbon electrodes (SPE), carbon nanotube modified screen printed electrodes, and carbon paste electrodes. We compare the analytical performance of the different electrodes in terms of sensitivity and limit of detection, concluding that carbon electrodes modified with high surface area material exhibit an improvement of sensitivity. In terms of limit of detection, increasing the electrode surface area however does not improve the detection limit; the limit of detection is similar for all electrodes studied.

  • ionic liquid carbon nanotube modified screen printed electrodes and their potential for Adsorptive Stripping Voltammetry
    Electroanalysis, 2014
    Co-Authors: Patrick Gan, John S Foord, Richard G. Compton
    Abstract:

    Compared with paraffin oil, the use of ionic liquids as a binder in carbon paste type electrodes was shown to greatly enhance the accumulation of analytes, as illustrated with 17α-ethynylestradiol as a model. The ionic “liquid” n-octyl-pyridinium hexafluorophosphate [C8py][PF6] was most efficient among several ionic liquids investigated. Such preconcentration allowed a [C8py][PF6]-multiwalled carbon nanotubes (MWCNTs) (95 : 5 w/w) composite electrode to be useful for Adsorptive Stripping Voltammetry. Screen-printed electrodes modified with [C8py][PF6]-MWCNTs were developed and were able to achieve high sensitivity during Adsorptive Stripping voltammetric measurements under optimised conditions.

  • Selective Curcuminoid Separation and Detection via Nickel Complexation and Adsorptive Stripping Voltammetry
    Electroanalysis, 2012
    Co-Authors: David M. Wray, Christopher Batchelor-mcauley, Richard G. Compton
    Abstract:

    Curcumin is a widely studied biologically active redox molecule. Although sensitive, electrochemical methods are commonly hindered by their lack of specificity. This article demonstrates how curcumin may be readily separated from other structurally and electrochemically similar redox moieties. This separation is achieved through exploitation of the molecules diketone functionality providing a route for its selective chelation to nickel(II). Recovery of the curcumin from the nickel complex is achieved simply and quantitatively through acidification of the precipitate. Adsorptive Stripping Voltammetry at a carbon screen-printed electrode (SPE) is utilised both as a method for evidencing the effectiveness of the separation technique but further as a procedure for the analytical quantification of the curcumin concentration.

  • the use of nano carbon as an alternative to multi walled carbon nanotubes in modified electrodes for Adsorptive Stripping Voltammetry
    Sensors and Actuators B-chemical, 2012
    Co-Authors: Tsz W B Lo, Leigh Aldous, Richard G. Compton
    Abstract:

    Abstract We report the advantageous use of nano-carbon black as a much cheaper alternative to multiwalled carbon nanotubes as an electrode modifier for use in Adsorptive Stripping Voltammetry. Namely, the Adsorptive Stripping Voltammetry (AdsSV) of nicotine is compared and contrasted at an unmodified glassy carbon (GC) electrode and GC electrodes modified with either bamboo multiwalled carbon nanotubes (MWCNT) or carbon black. The approximately spherical, primary carbon black particles used possessed an average radius of 7 nm, and are a form of ‘nano-carbon’. Their immobilisation on a GC resulted in a nanostructured surface with a large active surface area. Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV) and Differential Pulse Voltammetry (DPV) were performed using the various systems. SWV resulted in a Limit of Detection (LOD) of 12.4 ± 0.2 μM at bare GC. CV gave the lowest LOD results for MWCNT and nano-carbon modified electrodes, with LOD values of 5.0 ± 0.3 and 2.0 ± 0.3 μM. Nano-carbon is highlighted to be a cheap, highly effective electrode modifier which facilitates the electroanalytical quantification of physiologically relevant concentrations of nicotine by AdsSV.

  • The Convenient Determination of Palladium at a Solid Electrode via Adsorptive Stripping Voltammetry at a Glassy Carbon Electrode Modified with a Random Array of Mercury Nanodroplets
    Electroanalysis, 2008
    Co-Authors: Poobalasingam Abiman, Gregory G. Wildgoose, Lei Xiao, Richard G. Compton
    Abstract:

    The detection of palladium using Adsorptive Stripping Voltammetry reported by Wang et al. (J. Wang, K. Varughese Anal. Chim. Acta 1987, 199, 185 [3]) at a hanging mercury drop electrode is extended to a more convenient solid electrode. To this end a random array of 3.5×108 mercury nanodroplets per cm2 (65 nm average diameter) was electrodeposited on a glassy carbon substrate. Adsorptive Stripping Voltammetry was performed using 2×10-4 M dimethylglyoxime as a chelating agent for the Pd(II) ion, with accumulation at -0.20 V vs. SCE for 120 s and a linear detection range of 5–150 µM was determined with a limit of detection of 1.6 µM.

Olga Domínguez Renedo - One of the best experts on this subject based on the ideXlab platform.

  • determination of lamotrigine by Adsorptive Stripping Voltammetry using silver nanoparticle modified carbon screen printed electrodes
    Talanta, 2007
    Co-Authors: Encarnacion Burgoa M Calvo, Olga Domínguez Renedo, Julia Arcos M Martinez
    Abstract:

    Abstract Carbon screen-printed electrodes (CSPE) modified with silver nanoparticles present an interesting alternative in the determination of lamotrigine (LTG) using differential pulse Adsorptive Stripping Voltammetry. Metallic silver nanoparticle deposits have been obtained by electrochemical deposition. Scanning electron microscopy measurements show that the electrochemically synthesized silver nanoparticles are deposited in aggregated form. The detection limit for this analytical procedure was 3.72 × 10−7 M. In terms of reproducibility, the precision of the above mentioned method in %R.S.D. values was calculated at 2.58%. The method was applied satisfactorily to the determination of LTG in pharmaceutical preparations.

  • speciation of antimony by Adsorptive Stripping Voltammetry using pyrogallol
    Talanta, 2007
    Co-Authors: Jesus Gomez M Gonzalez, Olga Domínguez Renedo, Julia Arcos M Martinez
    Abstract:

    This paper describes a new procedure for the determination of Sb (III) and Sb (V) by differential pulse Adsorptive Stripping Voltammetry (DPAdSV) using pyrogallol as a complexing agent. The selection of the experimental conditions was made using experimental design methodology. The detection limits obtained were 1.03x10(-10) and 9.48x10(-9)mol dm(-3) for Sb (III) and Sb (V), respectively. In order to carry out the simultaneously determination of both antimony species a partial least squares regression (PLS) is employed to resolve the voltammetric signals from mixtures of Sb (III) and Sb (V) in the presence of pyrogallol. The relative error in absolute value is less than 0.5% when concentrations of several mixtures are calculated. Moreover, the solution is analyzed for any possible effects of foreign ions. The procedure is successfully applied to the speciation of antimony in pharmaceutical preparations and water samples.

  • Determination of oxcarbazepine by Square Wave Adsorptive Stripping Voltammetry in pharmaceutical preparations
    Journal of pharmaceutical and biomedical analysis, 2006
    Co-Authors: M. Encarnación Burgoa Calvo, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    Abstract A procedure for the determination of oxcarbazepine (OXC) by Square Wave Adsorptive Stripping Voltammetry (SWAdSV) has been optimized. Selection of the experimental parameters was made using experimental design methodology. The detection limit was 1.74 × 10 −7  mol dm −3 . This method was used to determine oxcarbazepine in pharmaceutical preparations.

  • Speciation of Antimony by Adsorptive Stripping Voltammetry Using Pyrogallol Red
    Electroanalysis, 2006
    Co-Authors: M. Jesús Gómez González, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    This paper proposes a procedure for the speciation of antimony by Differential Pulse Adsorptive Stripping Voltammetry (DPAdSV) using pyrogallol red (PGR) as a complexing agent. It employs a Partial Least Squares regression (PLS) in the resolution of strongly overlapping voltammetric signals obtained from mixtures of Sb(III) and Sb(V) in the presence of pyrogallol red. The absolute value of the relative error was less than 3.5% when concentrations of several mixtures were calculated, the minimum concentrations being 9.98×10−9 mol dm−3 and 4.87×10−8 mol dm−3 for Sb(III) and Sb(V), respectively. Any undue effects caused by the presence of foreign ions in the solution were also analyzed. The procedure was successfully applied to the speciation of antimony in pharmaceutical preparations.

  • Optimization of the experimental parameters in the determination of lamotrigine by Adsorptive Stripping Voltammetry
    Analytica Chimica Acta, 2005
    Co-Authors: M. Encarnación Burgoa Calvo, Olga Domínguez Renedo, M. Julia Arcos Martínez
    Abstract:

    Abstract This paper describes a procedure that has been optimized for the determination of lamotrigine (LTG) by Adsorptive Stripping Voltammetry (AdSV). Two different voltammetric techniques, namely differential pulse Adsorptive Stripping Voltammetry (DPAdSV) and square wave Adsorptive Stripping Voltammetry (SWAdSV) were used. In order to determine the most sensitive technique, optimization of the experimental parameters using experimental design methodology was carried out for each technique. The detection limits obtained, 4.68 × 10 −9  mol dm −3 for DPAdSV and 5.02 × 10 −9  mol dm −3 for SWAdSV, show that both techniques are almost the same sensitive for the analysis of lamotrigine. Finally, this method was used to determine lamotrigine in pharmaceutical preparations and in spiked human plasma samples.

Christopher M.a. Brett - One of the best experts on this subject based on the ideXlab platform.

  • Determination of Chromium(VI) by Batch Injection Analysis and Adsorptive Stripping Voltammetry
    Analytical Letters, 2003
    Co-Authors: Christopher M.a. Brett, Olga M.s. Filipe, C. Susanna Neves
    Abstract:

    Abstract A new sensitive voltammetric method is presented for the determination of trace levels of Cr(VI). The method is based on square wave Adsorptive Stripping Voltammetry (AdSV) in conjunction with the electrochemical batch injection analysis technique at mercury thin-film electrodes. The determination of chromium is made in the presence of cupferron as ligand. Relevant experimental parameters are explored and optimized, such as injection mode, cupferron concentration, accumulation potential and time, and square wave parameters. A preconcentration time of 20 s at −0.8 V vs. SCE results in a detection limit of 32 nM. The relative standard deviation for 12 measurements of 0.12 µM was 6.5%. Possible interferences by other trace metals are considered.

  • Square wave Adsorptive Stripping Voltammetry of nickel and cobalt at wall‐jet electrodes in continuous flow
    Electroanalysis, 1996
    Co-Authors: Christopher M.a. Brett, M. Beatriz Q. Garcia, José L. F. C. Lima
    Abstract:

    Square wave Adsorptive Stripping Voltammetry (SWAdSV) of nickel and cobalt at wall-jet electrodes in a continuous flow system has been evaluated. Characteristics and advantages relative to differential pulse Adsorptive Stripping Voltammetry (DPAdSV) in continuous flow systems are explored. Under optimized experimental conditions, sensitivity is approximately a factor of ten higher than DPAdSV, and onenanomolar detection limits are achieved. Solution deoxygenation is unnecessary and sample throughput is increased.

  • Adsorptive Stripping Voltammetry of cobalt and nickel in flow systems at wall‐jet electrodes
    Electroanalysis, 1991
    Co-Authors: Christopher M.a. Brett, Ana Maria Oliveira Brett, Jorge Pereira
    Abstract:

    Adsorptive Stripping Voltammetry of cobalt and nickel in flow systems at wall-jet mercury thin-film electrodes has been investigated and assessed. A HEPES biological buffer with sodium perchlorate electrolyte was employed with excess nioxime, or dimethylglyoxime, ligand, and the accumulated complex on the mercury film surface determined by differential pulse reduction. Concentrations down to 1 nM can be routinely measured. Results at the wall-jet electrode, supported by evidence from LSV and impedance measurements at rotating and stationary electrodes respectively, show the viability of the method.