Vernier Go Direct Manual page 4

Selecting Experiment Type
The three options for Experiment Types are
Cyclic Voltammetry
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Bulk Electrolysis
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Open Circuit Potentiometry
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1. Connect the sensor following the steps in the Getting Started section of this
user manual. Select Data Collection from the Sensors menu to access the
Voltammetry Settings menu.
2. Select the desired experiment type. Cyclic Voltammetry (shortened to
Voltammetry) is selected by default. The default parameters are appropriate for
measuring a cyclic voltammogram for common samples in a buffer solution.
You may want to adjust these settings according to the student instructions in
the Electrochemistry Experiments with the Go Direct Cyclic Voltammetry
System e-book.
3. Click or tap Collect to begin data collection. The run will stop automatically or
you can choose to end it early.
4. Name your sample appropriately. To do this, navigate to the table screen. Tap
(LabQuest 2) or double-tap (LabQuest 3) on the column header of the data set
you wish to rename. Enter a name for the sample and tap Done.
5. From the Graph menu, analyze the voltammogram by selecting the desired
peak. From the Analyze menu, choose Statistics. You may also wish to
analyze your data using the integral function also located under the Analyze
menu.
6. When you are ready to change your sample, carefully remove the Cyclic
Voltammetry System from the stand by pulling back on the top tab (Figure 3).
Figure 2
7. With the SPE still inserted in the Cyclic Voltammetry System, rinse the SPE
with buffer solution, and dry it by gently blotting the electrode surface with a
piece of paper towel. Important: Do not invert the Cyclic Voltammetry
System with a damp SPE attached. You want to avoid getting liquid inside the
SPE connector.
8. Repeat Steps 2–7 for as many samples as you test. To change the parameters
between runs, tap Data Collection from the Sensors menu on the Meter screen.
9. When you are finished with you experiment, discard the solution and SPE as
instructed. Click or tap on the File Menu to Save or Export your data.
Changing the Settings in LabQuest App
On the Meter screen, select Data Collection from the Sensors menu. This will
show the Voltammetry Settings dialog. You will set the Experiment type you wish
to perform here. There are multiple parameters listed in the dialog box that will
vary based on the experiment you have selected.
Cyclic Voltammetry
In this experiment type, the electrode potential ramps linearly with time in a preset
waveform, often through the electroactive species' standard potential, which
allows for the investigation of the resulting electrochemical species generated at
the electrode surface. The rate of voltage changes over time during each of the
segments in the waveform, known as the experiment's sweep rate. The potential is
measured between the working electrode and the reference electrode on the SPE,
while the current is measured between the working electrode and the counter
electrode on the SPE.
Number of Segments: You will be able to choose from a 1-, 2-, or 3-segment
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CV. This is the number of segments in the potentiostat's waveform. The
number of segments determines the number of potentials you must set. One-
segment will be linear sweep voltammetry with simply an initial and final
potential setting. A two-segment CV will have an initial and final potential,
along with one switching potential. A three-segment CV will have an initial
and final potential, along with two switching potentials.
Potentials: You will need to set each potential to dictate the potentiostat's
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waveform, including the Initial and Final Potentials, along with applicable
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Figure 3