Procedure for obtaining a cyclic voltammogram

1. Sign log book.
2. Turn on power.  The Cell mode should be on Standby.
3. Fill the cell approximately 2/3 full with the electrolyte solution (0.1 M TBAP in solvent), place the small stir bar in the cell, and place the electrodes in the cell.  (TBAP = tetrabutylammonium perchlorate.  There are three electrodes: working, auxillary and reference.  The working and auxillary electrodes are platinum and the reference electrode is Ag/AgCl). Turn the stirrer on.
4. Connect the wires to the electrodes ( red - auxillary; black - working; white - reference).  Be sure to check that the bottom of the working and reference electrodes are about the same level.
5. Set E1 to zero.  This is your starting voltage. Turn the Display knob to App E and adjust the E1 knob to the desired potential.
6. Set the upper and lower limits for your solvent.  For CH₂Cl₂ and CH₃CN, the upper limit should be +1.50 V and the lower limit - 1.00 V. (Turn the Display knob to +Lim or -Lim and adjust the  E Limit + - knob for the appropriate value)
7. Remove the cover and turn on the Houston plotter.  Load the paper by sliding it into the grooves at the bottom and left side of the plotter. Slide down the load button to hold the paper down.
8. Turn off the stirrer and turn the Cell mode to Cell.
9. Place the Standby/Record switch on the plotter to Record.
10. Turn the Function knob to E1, and then back to hold.  This will place the pen on the recorder at zero (or whatever the E1 setting is).
11. Push the Direction toggle switch to Positive, check the scan rate (typically 250 mV) by going to Display and adjusting with the Scan Rate knob.
12. Turn the Function knob to Scan and watch the plotter to see if everything is on scale.
13. If the pen holder stays on scale, turn the Function knob to E1, and then to hold. Place the pen in the holder, push the Direction toggle to Positive, place the Pen down (on plotter) and turn the Function knob to Scan.
14.  When the pen does one cycle, lift the pen (Pen Up), go back to E1, then hold on the Function knob.
15. Turn the Cell mode to Standby.
16. Place in your sample (approximately enough to cover the face of a dime) and turn on the stirrer.
17. After the sample has dissolved, repeat steps 8 - 15.
18. When finished, rinse out the cell with acetone and place the waste in the waste container.  Be careful not to lose the stir bar.  Rinse the electrodes with acetone.  Turn off the BAS CV-27 electroanalyzer. Place the plotter on Standby, turn off the plotter and cover.
 

Be sure to include the following information on your plot:
your name
date
electrolyte solution
compound (electroanalyte)
scan rate
electrodes
upper and lower limits
starting potential
scan direction

You should include the voltammogram of your solvent along with the voltammogram of your compound(s).

CHEM4204 Experiment list

Revised 11/22/02