Chronoamperometry Experimental Sequence

Framework™ creates a runner window, and the Chronoamperometry.EXP script is run in this window.

The script creates the Setup dialog box, which becomes the active window and accepts changes in the experimental parameters. This Setup window remembers the experimental settings from the last time this script was run. To restore the parameters to the values defined in the script, click the Default button. If the Advanced Pstat Setup is in the On position, a second Setup dialog box contain hardware configuration details becomes the active window, allowing you to modify the hardware configuration used during the experiment.

The script next obtains the use of the potentiostat specified during Setup and opens the data file using the Output File name. If the potentiostat is in use or the file cannot be opened, the script returns you to the Setup dialog box.

The file header information is written to the data file, before data-acquisition. This header information includes: Tags identifying possible analyses The current time and date A list of the Setup parameters and hardware configuration.

If Init. Delay is on, then the cell is turned or left off and the specimen’s Eoc is measured for the time specified as the Init. Delay time, or until the potential stabilizes to a value less than the stability setting. A plot of potential versus time is always displayed. The last measured potential is recorded as Eoc. If Init. Delay is off, this step is skipped and Eoc is assumed to be 0.0 V vs. Ref.

The script conditions the electrode if Conditioning was specified in the Setup. Conditioning is done by applying a fixed potential for a defined time with the stirrer turned on. A plot of current versus time is displayed during the Conditioning. No data are saved during this step.

The electrode and the solution are allowed to equilibrate for a defined time. The cell is turned on during this step, the Pre-step Voltage is applied, and the stirrer is off. No data are saved during this step.

Finally the actual data-acquisition process starts. The potential of the sample is held at the Pre-step Voltage for the Pre-step delay. This information is stored with the data file and is intended to show that the user has selected a voltage where no appreciable current occurs. The potential is then stepped to Step 1 Voltage and held at that value for Step 1 time . The potential is then stepped to Step 2 Voltage and held at that value for Step 2 time . If Step 2 time is zero then the second step is skipped.Current and voltage readings at fixed time intervals (Sample Period) are taken during the steps in Chronoamperometry. If Autoranging was selected in Setup, at each point the current range is automatically switched to the optimal range for the measured cell current. If Positive Feedback IR Compensation has been selected all data is continuously corrected for IR-drop. If Current Interrupt IR Compensation has been selected, each potential is corrected for the measured IR-drop of the preceding point.Plots of I and E vs. time are displayed during the steps.

The data are written to the output file and the script cleans up and halts.When the scan is over, the cell is turned off. The acquired data are written to the output file. The script then waits for you to click the Skip button. When you do, the script closes everything that’s open, including the runner window.