TY - JOUR
T1 - Electrochemistry in organic solvents without supporting electrolyte using platinum microelectrodes
AU - Bond, A. M.
AU - Fleischmann, M.
AU - Robinson, J.
PY - 1984/5/25
Y1 - 1984/5/25
N2 - Most physical methods of measurement can be applied directly in non-aqueous solvents, including those of high resistance. Restrictions placed on electrochemical measurements by the need to add an electrolyte to reduce resistance problems may be minimised in the case of neutral molecules by the use of microelectrodes. A two-electrode, rather than a potentiostated three-electrode measuring system, is recommended to minimize noise. For oxidation of ferrocene at a platinum microelectrode with a radius of 25 μm, the steady-state diffusion-controlled limiting current in acetonitrile is essentially the same as in the presence of electrolyte. However, the shape of the voltammogram is distorted by ohmic iR drop. With radii < 1 μm, IR-drop effects are greatly reduced and close-to-conventional electrochemical data are obtained in the absence of any deliberately added electrolyte. In principle, electrode processes without electrolyte should be studied under conditions of the theoretically interesting one-ion problem, but secondary chemical reactions with traces of water, other impurities, or the solvent itself, are believed to produce conditions equivalent to the presence of an extremely dilute supporting electrolyte. The use of microelectrodes of radii < 1 μm should provide applications in fields such as monitoring of chemical reactions in high-resistance organic solvents, as well as an ability in analytical applications to use electrochemical detection after normal phase chromatographic separations.
AB - Most physical methods of measurement can be applied directly in non-aqueous solvents, including those of high resistance. Restrictions placed on electrochemical measurements by the need to add an electrolyte to reduce resistance problems may be minimised in the case of neutral molecules by the use of microelectrodes. A two-electrode, rather than a potentiostated three-electrode measuring system, is recommended to minimize noise. For oxidation of ferrocene at a platinum microelectrode with a radius of 25 μm, the steady-state diffusion-controlled limiting current in acetonitrile is essentially the same as in the presence of electrolyte. However, the shape of the voltammogram is distorted by ohmic iR drop. With radii < 1 μm, IR-drop effects are greatly reduced and close-to-conventional electrochemical data are obtained in the absence of any deliberately added electrolyte. In principle, electrode processes without electrolyte should be studied under conditions of the theoretically interesting one-ion problem, but secondary chemical reactions with traces of water, other impurities, or the solvent itself, are believed to produce conditions equivalent to the presence of an extremely dilute supporting electrolyte. The use of microelectrodes of radii < 1 μm should provide applications in fields such as monitoring of chemical reactions in high-resistance organic solvents, as well as an ability in analytical applications to use electrochemical detection after normal phase chromatographic separations.
UR - http://www.scopus.com/inward/record.url?scp=0021448945&partnerID=8YFLogxK
U2 - 10.1016/0368-1874(84)87106-3
DO - 10.1016/0368-1874(84)87106-3
M3 - Article
AN - SCOPUS:0021448945
SN - 0022-0728
VL - 168
SP - 299
EP - 312
JO - Journal of Electroanalytical Chemistry and Interfacial Electrochemistry
JF - Journal of Electroanalytical Chemistry and Interfacial Electrochemistry
IS - 1-2
ER -