The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform

Hideaki Kano - One of the best experts on this subject based on the ideXlab platform.

Stella M Tzouwarakarayanni - One of the best experts on this subject based on the ideXlab platform.

  • electrocatalysis of sulphide with a Cellulose Acetate Film bearing 2 6 dichlorophenolindophenol application to sewage using a fully automated flow injection manifold
    Talanta, 2000
    Co-Authors: Ageliki B Florou, Mamas I Prodromidis, Miltiades I Karayannis, Stella M Tzouwarakarayanni
    Abstract:

    Abstract The application of an electrochemical sensor, based on a glassy carbon electrode, modified with a Cellulose Acetate polymeric Film bearing 2,6-dichlorophenolindophenol (CA/DCPI-CME), for flow injection analysis of sulphide, is described. The overall reaction was found to obey a catalytic regeneration mechanism (EC mechanism) and the electrochemical rate constant kf for the electrocatalytic oxidation of sulphide was evaluated. The modified electrodes were mounted in a flow-injection manifold, poised at +0.08 mV versus Ag/AgCl/3 M KCl at pH 7.25 and utilised for the determination of sulphide in urban waste samples. The proposed method correlates well with a colorimetric method. Parameters such as working pH, sample size, flow rate and temperature were studied. Interferants of various compounds normally present in real samples were also tested. Calibration graphs were linear over the range 0.02–1 mM sodium sulphide for CA/DCPI-CMEs hydrolysed in KOH for 6 min. The throughput was 25 samples per h and the R.S.D. was 1.2% (n=7) for 0.1 mM sodium sulphide. Recoveries for spiked urban waste samples ranged from 99 to 120%. The sensor remained active for more than 2 weeks under specified conditions.

  • flow electrochemical determination of ascorbic acid in real samples using a glassy carbon electrode modified with a Cellulose Acetate Film bearing 2 6 dichlorophenolindophenol
    Analytica Chimica Acta, 2000
    Co-Authors: Ageliki B Florou, Mamas I Prodromidis, Miltiades I Karayannis, Stella M Tzouwarakarayanni
    Abstract:

    Abstract An ascorbate sensor based on a glassy carbon electrode modified with a Cellulose Acetate polymeric Film bearing 2,6-dichlorophenolindophenol (CA/DCPI-CME) was constructed. The overall reaction obeys a catalytic regeneration mechanism (EC mechanism) and the electrochemical rate constant kf for the electrocatalytic oxidation of ascorbic acid was evaluated. The modified electrodes were mounted in a flow injection (FI) manifold, poised at +100 mV versus Ag/AgCl/3 M KCl at pH 6.5 and utilized for the determination of ascorbic acid in beverages and pharmaceuticals. Good correlation with a reference method was attained. Interferents of various molecular sizes were tested. Calibration graphs were linear over the range 0.02–1 and 0.1–6 mM ascorbic acid for CA/DCPI sensors hydrolyzed in KOH and ZnCl2 solution, respectively. The throughput was 25 samples per hour and the CV was for a 0.4 mM ascorbic acid solution 0.75 (n=14) and 1.2% (n=10) for CA/DCPI sensors hydrolyzed in KOH and ZnCl2 solution, respectively. The recovery was 92–110%. The sensors showed very good repeatability and operational stability.

  • electrochemical behavior and analytical utility of a controlled porosity Cellulose Acetate Film bearing 2 6 dichlorophenolindophenol
    Electroanalysis, 2000
    Co-Authors: Ageliki B Florou, Mamas I Prodromidis, Miltiades I Karayannis, Stella M Tzouwarakarayanni
    Abstract:

    Glassy carbon electrodes coated with a Cellulose Acetate Film incorporating 2,6-dichlorophenolindophenol (CA/DCPI) were developed. At this multifunctional coating DCPI serves as a mediator for the electron transfer kinetics and in conjunction with the Cellulose Acetate’s size exclusion properties it results in a chemical sensor with great selectivity and stability. Access to the surface can be manipulated via controlled hydrolysis of the Film in KOH or ZnCl2 solutions. Different permeabilities are obtainable by hydrolyzing the Film over different time periods. Diffusion coefficients Dapp of these Films for analytes of different molecular sizes were determined with double step chronocoulometry. The electrochemical characteristics of the immobilized DCPI were explored using cyclic voltammetry. The formal potentials of the immobilized DCPI coating hydrolyzed in KOH, ZnCl2 and with ZnCl2 in the casting solution were found to be 70, 75, and 79 mV (vs. Ag/AgCl/ 3M KCl), respectively, at pH 6.5. The dissociation constants of the DCPI redox couple were found to be 5.2+ 0.1 (pKr) and 7.4+ 0.05 (pKo). The electrochemical rate constant k o of the of DCPI redox couple within the Film was also evaluated. The behavior of the sensor towards different reducing compounds was investigated. The sensors showed good operational and storage stability.

Rie Fujisawa - One of the best experts on this subject based on the ideXlab platform.

Ageliki B Florou - One of the best experts on this subject based on the ideXlab platform.

  • electrocatalysis of sulphide with a Cellulose Acetate Film bearing 2 6 dichlorophenolindophenol application to sewage using a fully automated flow injection manifold
    Talanta, 2000
    Co-Authors: Ageliki B Florou, Mamas I Prodromidis, Miltiades I Karayannis, Stella M Tzouwarakarayanni
    Abstract:

    Abstract The application of an electrochemical sensor, based on a glassy carbon electrode, modified with a Cellulose Acetate polymeric Film bearing 2,6-dichlorophenolindophenol (CA/DCPI-CME), for flow injection analysis of sulphide, is described. The overall reaction was found to obey a catalytic regeneration mechanism (EC mechanism) and the electrochemical rate constant kf for the electrocatalytic oxidation of sulphide was evaluated. The modified electrodes were mounted in a flow-injection manifold, poised at +0.08 mV versus Ag/AgCl/3 M KCl at pH 7.25 and utilised for the determination of sulphide in urban waste samples. The proposed method correlates well with a colorimetric method. Parameters such as working pH, sample size, flow rate and temperature were studied. Interferants of various compounds normally present in real samples were also tested. Calibration graphs were linear over the range 0.02–1 mM sodium sulphide for CA/DCPI-CMEs hydrolysed in KOH for 6 min. The throughput was 25 samples per h and the R.S.D. was 1.2% (n=7) for 0.1 mM sodium sulphide. Recoveries for spiked urban waste samples ranged from 99 to 120%. The sensor remained active for more than 2 weeks under specified conditions.

  • flow electrochemical determination of ascorbic acid in real samples using a glassy carbon electrode modified with a Cellulose Acetate Film bearing 2 6 dichlorophenolindophenol
    Analytica Chimica Acta, 2000
    Co-Authors: Ageliki B Florou, Mamas I Prodromidis, Miltiades I Karayannis, Stella M Tzouwarakarayanni
    Abstract:

    Abstract An ascorbate sensor based on a glassy carbon electrode modified with a Cellulose Acetate polymeric Film bearing 2,6-dichlorophenolindophenol (CA/DCPI-CME) was constructed. The overall reaction obeys a catalytic regeneration mechanism (EC mechanism) and the electrochemical rate constant kf for the electrocatalytic oxidation of ascorbic acid was evaluated. The modified electrodes were mounted in a flow injection (FI) manifold, poised at +100 mV versus Ag/AgCl/3 M KCl at pH 6.5 and utilized for the determination of ascorbic acid in beverages and pharmaceuticals. Good correlation with a reference method was attained. Interferents of various molecular sizes were tested. Calibration graphs were linear over the range 0.02–1 and 0.1–6 mM ascorbic acid for CA/DCPI sensors hydrolyzed in KOH and ZnCl2 solution, respectively. The throughput was 25 samples per hour and the CV was for a 0.4 mM ascorbic acid solution 0.75 (n=14) and 1.2% (n=10) for CA/DCPI sensors hydrolyzed in KOH and ZnCl2 solution, respectively. The recovery was 92–110%. The sensors showed very good repeatability and operational stability.

  • electrochemical behavior and analytical utility of a controlled porosity Cellulose Acetate Film bearing 2 6 dichlorophenolindophenol
    Electroanalysis, 2000
    Co-Authors: Ageliki B Florou, Mamas I Prodromidis, Miltiades I Karayannis, Stella M Tzouwarakarayanni
    Abstract:

    Glassy carbon electrodes coated with a Cellulose Acetate Film incorporating 2,6-dichlorophenolindophenol (CA/DCPI) were developed. At this multifunctional coating DCPI serves as a mediator for the electron transfer kinetics and in conjunction with the Cellulose Acetate’s size exclusion properties it results in a chemical sensor with great selectivity and stability. Access to the surface can be manipulated via controlled hydrolysis of the Film in KOH or ZnCl2 solutions. Different permeabilities are obtainable by hydrolyzing the Film over different time periods. Diffusion coefficients Dapp of these Films for analytes of different molecular sizes were determined with double step chronocoulometry. The electrochemical characteristics of the immobilized DCPI were explored using cyclic voltammetry. The formal potentials of the immobilized DCPI coating hydrolyzed in KOH, ZnCl2 and with ZnCl2 in the casting solution were found to be 70, 75, and 79 mV (vs. Ag/AgCl/ 3M KCl), respectively, at pH 6.5. The dissociation constants of the DCPI redox couple were found to be 5.2+ 0.1 (pKr) and 7.4+ 0.05 (pKo). The electrochemical rate constant k o of the of DCPI redox couple within the Film was also evaluated. The behavior of the sensor towards different reducing compounds was investigated. The sensors showed good operational and storage stability.

Tomoya Ohno - One of the best experts on this subject based on the ideXlab platform.