University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Scientific Papers of the University of Pardubice

  • Publisher:
  • FAD Code: SPUP
  • CODEN: SVPVA9
  • ISSN: 1211-5541
  • Abbreviation: Sci. Pap. Univ. Pardubice, Ser. A
  • DOI Prefix: NA
  • Language: Czech

Citations 3

"Charge Transfer Across The Interface Between Two Immiscible Electrolyte Solutions And Analytical Applications"
Sci. Pap. Univ. Pardubice, Ser. A 1998 Volume 3, Issue 1 Pages 275-291
Alemu, H.;Solomon, T.;Hundhammer, B.;Kalcher, K.;Schachl, K.

Abstract: The transfer of several ions across the water/2-chloroethyl ether and water/o-dichlorobenzene interfaces was studied by DC and AC cyclic voltammetry. The standard Gibbs energies of ion transfer were determined based on the tetraphenylarsonium tetraphenylborate assumption. The results were compared with theoretical data calculated from an ionic solvation model. The transfer of transition metal-terpyridine complexes across the water/nitrobenzene interface also was studied and from the voltammetric measurements the standard Gibbs energies of transfer were evaluated. An amperometric detector based on membrane stabilized interface between two immiscible electrolyte solutions was developed. It was tested in a flow injection system for the determination of anions and cations. The detection limit of the detector is ~5 x 10^-7 M for the ions studied.
Anions Cations Amperometry Voltammetry

"Determination Of Hydrogen Peroxide With Sensors Based On Heterogenous Carbon Materials Modified With Manganese Dioxide"
Sci. Pap. Univ. Pardubice, Ser. A 1998 Volume 3, Issue 1 Pages 41-55
Schachl, K.;Alemu, H.;Kalcher, K.;Jezkova, J.;Svancara, I.;Vytras, K.

Abstract: Three different types of MnO2-modified electrodes were investigated for their electrochemical response toward hydrogen peroxide: a bulk-modified carbon paste electrode, a film-modified carbon paste electrode and a film-modified screen printed electrode. The sensors were characterized by voltammetric (cyclic voltammetry, linear sweep voltammetry) and amperometric methods (stationary and flow conditions). The best responses were obtained with a MnO2 film-modified screen printed carbon electrode which could be used as an electrochemical detector in flow injection analysis (FIA) using a NH3/NH4Cl buffer (0.2 M, pH 9.5) as a carrier. With FIA a detection limit (3s) of 0.26 µg L-1 could be achieved; the peak current was linear to the H2O2 concentration from 1 to 200.000 µg L-1. The method could be successfully applied to the determination of H2O2 in various samples (cosmetic and medical products, rain water). With flow injection a sample frequency of 60 h-1 can be achieved.
Hydrogen peroxide Rain Commercial product Commercial product Electrode Electrode Electrode Apparatus Detector Buffer

"The Effect Of Various Polyelectrolytes On Alcohol Oxidase/horseradish Peroxidase/ferrocene Modified Carbon Paste Electrodes"
Sci. Pap. Univ. Pardubice, Ser. A 1998 Volume 3, Issue 1 Pages 31-39
Larsson, N.;Gorton, L.

Abstract: Two enzyme based alcohol biosensors were constructed by co-immobilizing alcohol oxidase and horseradish peroxidase into a carbon paste matrix. The effects of chemical modifying HRP, adding a mediator and different polyelectrolytes were examined, aiming at better operational stability when used in a flow injection system. The electrodes are characterized (sensitivity, detection limit, operational stability) when operated at an applied working potential of -50 mV vs. Ag/AgCl.
Electrode Sensor Electrode Apparatus Optimization