Analysis of Voltammetric Half-Wave Potentials in Low Ionic Strength Solutions and Voltammetric Measurement of Ion Impurity Concentrations
Abstract
An analytic equation is presented that allows the prediction of steady-state voltammetric half-wave potentials as a function of electrolyte concentration in low ionic strength solutions for an electrode of arbitrary geometry and size. The equation is tested for the oxidation of ferrocene in acetonitrile at 2.4 - 20 micro m platinum microdisk electrodes for electrolyte (tetra-n-butylammonium perchlorate) concentrations between 10(-1) and 4 x 10 to the 9th power M, and in acetonitrile solutions containing no intentionally added electrolyte. An analytical method for measuring ion impurity concentration, based on steady-state microelectrode voltammetry, is proposed and used to measure micro M ionic impurities in acetonitrile. The role of ionic solution impurities on voltammetric measurements in the absence of intentionally added electrolyte is quantified and a criterion for the minimum number of ions required to observe sigmoidally-shaped voltammetric curves at is proposed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 17, 1990
- Accession Number
- ADA229774
Entities
People
- Bradford D Pendley
- Henry S. White
- Héctor D. Abruña
- John D. Norton
- Wendy E. Benson
Organizations
- University of Minnesota