Calculate Cottrell Equation

The Calculate Cottrell Equation command is used in current-vs.-tau–1/2 plots to determine the values of the parameters in the Cottrell equation for Chronoamperometry experiments. In order to use this command you must do a linear fit on the current-vs.-tau–1/2 plot.


Select the Second Chart tab to show the current-vs.-tau–1/2 plot.

Use the Linear Fit command to define a region of the plot.

Select the Calculate Cottrell Equation command from the document menu. The Specify Linear Region to Fit window appears.

Click the desired line, then click the OK button.

The Cottrell Equation window appears. Enter three of the four parameters of the Cottrell equation. The slope of the line with the user-entered parameters are used to determine the value for the one unknown, using the relationship that the slope = (nFAD1/2C)/π1/2.

Click the Calculate button.