The Experts below are selected from a list of 177 Experts worldwide ranked by ideXlab platform

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

  • Anodic Stripping Voltammetry of silver nanoparticles aggregation leads to incomplete Stripping
    ChemistryOpen, 2015
    Co-Authors: Samantha J Cloake, Her Shuang Toh, Patricia T Lee, Chris Salter, C Johnston, Richard G. Compton
    Abstract:

    The influence of nanoparticle aggregation on Anodic Stripping Voltammetry is reported. Dopamine-capped silver nanoparticles were chosen as a model system, and melamine was used to induce aggregation in the nanoparticles. Through the Anodic Stripping of the silver nanoparticles that were aggregated to different extents, it was found that the peak area of the oxidative signal corresponding to the Stripping of silver to silver(I) ions decreases with increasing aggregation. Aggregation causes incomplete Stripping of the silver nanoparticles. Two possible mechanisms of ‘partial oxidation’ and ‘inactivation’ of the nanoparticles are proposed to account for this finding. Aggregation effects must be considered when Anodic Stripping Voltammetry is used for nanoparticle detection and quantification. Hence, drop casting, which is known to lead to aggregation, is not encouraged for preparing electrodes for analytical purposes.

  • Determination of Sb(V) Using Differential Pulse Anodic Stripping Voltammetry at an Unmodified Edge Plane Pyrolytic Graphite Electrode
    Electroanalysis, 2012
    Co-Authors: Neil V. Rees, Richard G. Compton
    Abstract:

    Antimony(V) determination at an unmodified edge plane pyrolytic graphite (EPPG) electrode using Anodic Stripping Voltammetry (ASV) by depositing beyond the hydrogen wave is shown in this paper. By depositing beyond the hydrogen wave, we report a sensitive method to determine pentavalent antimony at a carbon electrode in 0.25 M HCl. Using differential pulse Anodic Stripping Voltammetry (DPASV), a bare EPPG electrode gave a detection limit of 5.8±0.02 nM without the need for surface modification. This level is greatly within the EU limit for drinking water of 40 nM.

  • Anodic Stripping Voltammetry of arsenic iii using gold nanoparticle modified electrodes
    Analytical Chemistry, 2004
    Co-Authors: Olga Nekrassova, And Michael E Hyde, Richard G. Compton
    Abstract:

    A novel method for the detection of arsenic(III) in 1 M HCl at a gold nanoparticle-modified glassy carbon electrode has been developed. The gold nanoparticles were electrodeposited onto the glassy carbon electrode via a potential step from +1.055 to −0.045 V vs SCE for 15 s from 0.5 M H2SO4 containing 0.1 mM HAuCl4. The resulting electrode surfaces were characterized with both AFM and cyclic Voltammetry. Anodic Stripping Voltammetry of arsenic(III) on the modified electrode was performed. After optimization, a LOD of 0.0096 ppb was obtained with LSV.

  • Anodic Stripping Voltammetry: An AFM Study of Some Problems and Limitations
    Electroanalysis, 2004
    Co-Authors: Michael E. Hyde, Craig E. Banks, Richard G. Compton
    Abstract:

    The use of Anodic Stripping Voltammetry for quantitative analytical measurements using solid electrodes is addressed in the light of generic limitations arising from i) electrode heterogeneity, ii) electrode morphology, iii) inhibited electrodeposition, and iv) incomplete Stripping of deposited metal in the Anodic sweep. It is shown, using direct imaging of electrode surfaces via AFM and optical microscopy, that each of the preceding factors may produce significant deviations from ideal electrode behavior. The use of atomic force microscopy to fully characterize any developed ASV procedures is strongly recommended. To ensure reproducible and accurate Stripping Voltammetry, steps should be taken to minimize the effects discussed.

  • Anodic Stripping Voltammetry with photochemical preconcentration at nanocrystalline TiO2 films: detection of Ag+ and Hg2+
    Electroanalysis, 2000
    Co-Authors: Marco F. Suárez, Andrew Mills, Russell G. Egdell, Richard G. Compton
    Abstract:

    Nanocrystalline TiO2 deposited on conducting glass plates is shown to be an excellent material for preconcentration of silver and mercury, via photochemical reaction, prior to their detection by Anodic Stripping Voltammetry (ASV). During the first stage of growth in the photoreduction of silver or mercury, 3D nuclei are formed on the TiO2 film. As the deposition proceeds micrometer size agglomerates grow on the surface. The conical morphology of the silver nuclei grown on a (110) rutile single crystal in the initial stages of growth suggests that there is a preferential deposition of silver at the centre of the growing nuclei. When the nuclei size reach a critical value (ca. 400 nm diameter, 40 nm height) the morphology changes to a globular shape without any preferential site for deposition on the surface of the silver nucleus. It was observed that micromolar concentrations of silver or mercury can be detected by Anodic Stripping Voltammetry and relatively large amounts of these metals (micrometer scale nuclei) can be loaded on the nanocrystalline TiO2 film surface. The latter opens the possibility of analytical applications of nanocrystalline TiO2 electrodes for the selective detection of silver or mercury via photochemical Anodic Stripping Voltammetry.

James A. Plambeck - One of the best experts on this subject based on the ideXlab platform.

Jun-der Lee - One of the best experts on this subject based on the ideXlab platform.

  • Preconcentration of trace metals in sea water matrix for differential pulse Anodic Stripping Voltammetry
    Analytica Chimica Acta, 1994
    Co-Authors: Jun-der Lee
    Abstract:

    Abstract A preconcentration procedure with two-step extraction was proposed to be used in conjunction with differential pulse Anodic Stripping Voltammetry (DPASV) for the determination of trace metals in sea water. The two-step extraction involved extraction of trace metals from sea water with dithiocarbamate into chloroform followed by backextraction with a Hg 2+ solution at pH 3.5, as previously reported. The aqueous solution containing simply the enriched metals and the nonreacted Hg 2+ was analysed by DPASV using a glassy carbon electrode. Anodic Stripping Voltammetry of the metals including Zn, Cd, Pb and Cu was conducted in the preconcentrated solution after adding 0.025 M KCl. The preconcentrated solution was observed not to cause any interference in the Anodic Stripping Voltammetry. Besides, the Hg 2+ could be in situ utilized as the source of the mercury film coated on the glassy carbon electrode, rendering it as an efficacious working electrode. The detection limits achieved were as low as 0.004 μg/1 for Zn, 0.002 μg/1 for Cd, 0.002 μg/1 for Pb and 0.003 μg/1 for Cu in sea water by DPASV coupled with the preconcentration procedure with an enrichment factor of 20. The analytical reliability was confirmed by checking with NASS-3 (NR-A4) open ocean sea water.

Howard D. Dewald - One of the best experts on this subject based on the ideXlab platform.

  • Differential pulse Anodic Stripping Voltammetry of barium and lead in gunshot residues.
    Forensic science international, 2001
    Co-Authors: Curt A. Woolever, Howard D. Dewald
    Abstract:

    Differential pulse Anodic Stripping Voltammetry (DPASV) has been applied for characterization and quantitative detection of barium and lead from gunshot residues (GSR). Previous electrochemical techniques have detected antimony and lead from GSR, however barium has never been detected. This technique allows for simultaneous detection of Ba and Pb that is simple, fast, and nondestructive.

  • Differential pulse Anodic Stripping Voltammetry of lead and antimony in gunshot residues
    Forensic Science International, 1999
    Co-Authors: Curt A. Woolever, Dustin E Starkey, Howard D. Dewald
    Abstract:

    Abstract Differential pulse Anodic Stripping Voltammetry (DPASV) using a glassy carbon/mercury film electrode (GC/MFE) has been applied for characterization and quantitative detection of gunshot residues (GSR). This technique allows for simultaneous detection of Pb and Sb from GSR hand swabs that is simple, fast, and non-destructive. The use of a KNO 3 /hydrazine sulfate matrix, instead of HCl, reduces possible interferences and allows for a small sample size to be used in analysis but yielding greater sensitivity.

Florence Geneste - One of the best experts on this subject based on the ideXlab platform.

  • Coupling of Anodic Stripping Voltammetry with Sampled-Current Voltammetry on an Electrode Array: Application to Lead Detection.
    Sensors (Basel Switzerland), 2020
    Co-Authors: Isabelle Mazerie, Florence Geneste
    Abstract:

    Electrochemical detection systems are very promising for pollution monitoring owing to their easy miniaturization and low cost. For this purpose, we have recently developed a new concept of device based on Electrodes Array for Sampled-Current Voltammetry (EASCV), which is compatible with miniaturization and portability. In this work, to improve the sensitivity of the analytical method, we added a preconcentration step before EASCV analysis, combining sampled-current Voltammetry with Anodic Stripping Voltammetry. Lead was chosen as analyte for this probe of concept owing to its high toxicity. The conditions for electrodeposition of lead on gold were optimized by means of under potential deposition. Current intensities 300 times higher than with linear sweep Anodic Stripping Voltammetry were obtained, showing the interest in the method. The value of the sampling time directly affected the sensitivity of the sensor given by the slope of the linear calibration curve. The sensor exhibited a limit of detection of 1.16 mg L−1, similar to those obtained with linear sweep Anodic Stripping Voltammetry.

  • Coupling of Anodic Stripping Voltammetry with sampled-current Voltammetry on an electrode array Application to lead detection
    Sensors, 2020
    Co-Authors: Isabelle Mazerie, Florence Geneste
    Abstract:

    Electrochemical detection systems are very promising for pollution monitoring owing to their easy miniaturization and low cost. For this purpose, we have recently developed a new concept of device based on Electrodes Array for Sampled-Current Voltammetry (EASCV), which is compatible with miniaturization and portability. In this work, to improve the sensitivity of the analytical method, we added a preconcentration step before EASCV analysis, combining sampled-current Voltammetry with Anodic Stripping Voltammetry. Lead was chosen as analyte for this probe of concept owing to its high toxicity. The conditions for electrodeposition of lead on gold were optimized by means of under potential deposition. Current intensities 300 times higher than with linear sweep Anodic Stripping Voltammetry were obtained, showing the interest in the method. The value of the sampling time directly affected the sensitivity of the sensor given by the slope of the linear calibration curve. The sensor exhibited a limit of detection of 1.16 mg L−1, similar to those obtained with linear sweep Anodic Stripping Voltammetry. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.