The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform

Cosme Moura - 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.

Božidar Ogorevc - One of the best experts on this subject based on the ideXlab platform.

  • bismuth film electrode for Anodic Stripping voltammetric determination of tin
    Analytica Chimica Acta, 2006
    Co-Authors: Emily A Hutton, Samo B Hocevar, Lea Mauko, Božidar Ogorevc
    Abstract:

    Abstract The bismuth film electrode (BiFE), in combination with Anodic Stripping voltammetry, offers convenient measurement of low concentrations of tin. The procedure involves simultaneous in situ formation of the bismuth film electrode on a glassy carbon substrate electrode, together with electrochemical deposition of tin, in a non-deaerated model solution containing bismuth ions, catechol as complexing agent and the metal analyte, followed by an Anodic Stripping scan. The BiFE is characterized by an attractive electroanalytical performance, with two distinct voltammetric Stripping signals corresponding to tin, accompanied with low background contributions. Several experimental parameters were optimized, such as concentration of bismuth ions and catechol, deposition potential, deposition time and pH of the model solution. In addition, a critical comparison is given with bare glassy carbon and mercury film electrodes, revealing the superior characteristics of BiFE for measurement of tin. BiFE exhibited highly linear behavior in the examined concentration range from 1 to 100 μg L−1 of tin (R2 = 0.997), an LoD of 0.26 μg L−1 tin, and good reproducibility with a calculated R.S.D. of 7.3% for 10 μg L−1 tin (n = 10). As an example, the practical applicability of BiFE was tested with the measurement of tin in a real sample of seawater.

  • recent advances in Anodic Stripping voltammetry with bismuth modified carbon paste electrodes
    Electroanalysis, 2006
    Co-Authors: Ivan Svancara, Samo B Hocevar, Božidar Ogorevc, Lucie Baldrianova, Eva Tesařova, Saber A A Elsuccary, Anastasios Economou, S Sotiropoulos, Karel Vytřas
    Abstract:

    In this article, the results of some recent investigations on two types of bismuth-modified carbon paste electrodes are presented. In the first study, the bismuth-film carbon paste electrode (BiF-CPE) operated in situ and employed in Anodic Stripping voltammetry of Cd(II) and Pb(II) at the low μg L−1 level was of interest in view of choosing the proper Bi(III)-to-Me(II) concentration ratios (where Me: Pb or Cd). Such optimization has resulted in significant improvement of detection limits down to 1.0 μg L−1 Cd and 0.8 μg L−1 for Pb, which allowed us to apply the BiF-CPE for analysis of selected real samples of tap and sea water. The BiF-CPE was also further investigated for its application in highly alkaline media. In this case, attention was focused on the complex-forming capabilities of the OH – ions and their effect on the Anodic Stripping characteristics of some heavy metals (i.e. Cd, Pb, Tl) as well as upon the formation of the bismuth film itself. The last example deals with the continuing characterization of the recently introduced carbon paste electrodes modified with bismuth powder (Bi-CPEs) which combine the advantageous properties of carbon paste material with the favorable electrochemical properties of bismuth. Three series of electrodes, differing either in the content of metallic bismuth (from 8 to 50% w/w) or in the type of the carbon powder used (two spectroscopic types of graphite and powdered glassy carbon), were compared and the respective relations to the optimal carbon paste composition evaluated. Attractive electroanalytical performance of the Bi-CPE in Anodic Stripping voltammetry is demonstrated for selected model mixtures of heavy metals (Mn, Zn, Cd, Pb, Tl, and In).

N. F. Zakharchuk - One of the best experts on this subject based on the ideXlab platform.

  • Determination of sub-micromolar amounts of sulfide by standard free Anodic Stripping voltammetry and Anodic Stripping voltammetric titration.
    Analytica chimica acta, 2009
    Co-Authors: T. V. Titova, N. S. Borisova, N. F. Zakharchuk
    Abstract:

    Abstract A novel electrochemical methods namely standard free Anodic Stripping voltammetry and Anodic Stripping voltammetric titration are proposed for determination of dissolved sulfide concentration. 2Ag +  + S 2−  → Ag 2 S reaction is used to provide the information. The Anodic Stripping voltammetric response of unreacted silver-ions at the glassy carbon electrode is used as analytical signal. Results reliability and accuracy are confirmed by analysis of model solutions, spiked natural and tap waters and recovery study, with a recovery of 100 ± 5% ( n  = 7) obtained. The approaches show the detection limit (3 σ blank ) of 2–5 × 10 −10  mol L −1 and the relative standard deviation of 2–5% for repeated measurements.

  • Determination of Thiols and Disulfides in Whole Blood and Its Fractions by Anodic Stripping Voltammetry and Anodic Stripping Voltammetric Titration
    Electroanalysis, 2006
    Co-Authors: N. F. Zakharchuk, N. S. Borisova, E Guselnikova, Kh. Z. Brainina
    Abstract:

    SH- and SS-groups content and their ratio is one of the most important factors of organism antioxidant system. Change in ratio of thiols to disulfides can serve as an indicator of oxidative stress. Anodic Stripping voltammetry and Anodic Stripping voltammetric titration (direct and reverse variants) methods are proposed for determination of thiols and disulfides concentration. Disulfides are preliminary reduced with sodium sulfite. Ag++RSHAgSR+H+ reaction is used to provide the information. Unreacted silver ions concentration is determined by Anodic Stripping voltammetry method using platinum working electrode. Calibration free method is suggested. The possibilities of express analysis of blood and its fractions are described. Reliability of results and accuracy are confirmed by model solutions analysis and recovery study of whole blood and its fractions. Results of whole blood, erythrocyte mass, plasma and serum taken from different groups of patients' investigations are given, that demonstrate perspectives of the application methods in clinical practice.

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.