Differential Pulse Voltammetry Experimental Sequence

  1. The Framework creates a runner window, and theDifferential Pulsed Voltammetry.expscript is run in this window.

  2. The script creates the Setup dialog box, which becomes the active window and accepts changes in the experimental parameters. This Setup box 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 on, a second Setup dialog box containing hardware-configuration details becomes the active window, so you can modify the hardware configuration.

  3. The script now obtains the use of the potentiostat and the multiplexer specified during setup.
  4. The potentiostat is initialized. By default, the potentiostat’s cell switch is turned Off when the potentiostat is attached to the script.
  5. All header information is written to the data files. Header information consists of the analysis tag, the time and date the experiment was started, and a list of the setup parameters.
  6. The script delays for a time set by the Quiet Time parameter.
  7. The current range is set to a range that allows the measurement of currents as big as the value of the Max I Setup parameter.

  8. The potential is set to Initial E and the cell is turned on

  9. If the Equilibration time parameter is greater than zero, the script delays for Tequil.

  10. Finally the actual scan occurs.

  11. N is the number of steps that have already occurred. At the start of the scan N is zero.

  12. The potential of the sample is set to Initial E plus N times the step height. If a mercury electrode has been specified in the Advanced menu, a New Drop pulse is issued. This potential is applied for Tstep – Tpulse. At the end of this time, a current measurement is made.

  13. A voltage equal to the pulse height is added to the cell voltage. The pulse-height sign is controlled so that the pulse is always in the direction of the final potential. This new voltage is held for Tpulse. At the end of this time, a second current measurement is made.

  14. The difference between the second and first current measurement is calculated and plotted versus the potential prior to the pulse.

  15. If Autoranging was selected in Setup and Tpulse is less than 20 ms, after each point the current range is automatically switched to the optimal range for the measured cell currents.

  16. Note: If Noise Rejection is active in Setup and if the pulse time is long enough (40 ms for 50 Hz or 33.3 ms for 60 Hz), each current measurement represents the average current measured over one complete line cycle (mains cycle).

  17. Steps 12 through 14 are repeated until the potential prior to the pulse equals the final potential.

  18. The cell is turned off. The script pauses to allow you to admire the curve you have just collected.