Voltammetric Measurement of Biomolecular Electron-Transfer Rates in Low Ionic Strength Solutions
Technical rept. 1 Jan-31 Oct 1990,
MINNESOTA UNIV MINNEAPOLIS DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE
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Numerical analysis of the sequential electron-transfer mechanism, A yields A e-, A yields A2 e- demonstrates that the rate at which A can be directly oxidized to A2 is inhibited in low ionic strength solutions by the coupled diffusion-migration of chemically-generated A. The latter species, A is produced within the depletion layer by the homogenous reaction, A A2, and is electrostatically repelled from electrode surface, thereby reducing the flux of A at the electrode surface. Steady-state voltammetric currents corresponding to two examples of this reaction mechanism, the oxidation of tetrathiafulvalene TTF and the reduction of tetracyanoquinodimethane TCNQ, have been measured at platinum microdisk electrodes over a wide range of electrolyte concentrations 0-0.1M.
- Theoretical Mathematics
- Atomic and Molecular Physics and Spectroscopy