|
The use of curve fitting for the analysis and interpretation of voltammetric data obtained while
working with microelectrodes is discussed as a useful exercise for introducing students to the
principle of problem solving using least-squares curve-fitting techniques. The advantages associated
with this approach to data processing over the approach where the limiting current
(i, L) alone is
used are discussed and its limitations are highlighted.
This technique was applied to the determination of unknown concentrations of ferrocyanide and
the most satisfactory recovery of concentrations was found when both the values of the formal
potential (E 0¢ ) and concentration (C) were varied to match the experimental results with an
equation characterizing the current potential curve for a reversible couple. In this case recoveries
of 100% ± 5% were obtained for the concentration range 5 x 10-4 to
1 x 10-2 M. It was also found
that Solver was unable to fit the equation when the sum of squared residuals was
<2 x 10-9. This
technique can be generalized for use with a number of other electrochemical experiments such as
polarography, rotating disk electrochemistry, and normal pulse polarography.
|
Citation
