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3.7.2
Programming the Voltammetry Waveform
Voltammetry waveforms are defined by points on an X-Y graph of
potential vs. time, as in Integrated Amperometry. Voltammetry
waveforms are defined from the
VOLTAMMETRY WAVEFORM
STEP
0
1
2
3
4
Help Message
Cyclic voltammetry programs consist of three steps, each with a time and
a potential. The first step is always at time zero. Since this cannot be
changed, the first value you enter will be the first potential. The first and
third steps have the same potential. To create a new waveform step, enter
the time first, and then the potential.
In the Voltammetry mode, the Dionex ED50A measures and reports the
current every 10 ms. Since the change in potential during each
measurement period must be equal, the available potentials are limited to
ensure that the potential change is an integer number of mV per 10 ms.
(The slowest scan rate is therefore 1 mV per 10 ms, or 0.1 V/s.) If the
potential you enter results in a noninteger change, the Dionex ED50A will
substitute the closest acceptable potential. You may want to use the
Select
To calculate the time for the second step of the waveform, divide the total
voltage scanned by the desired sweep rate.
Figure 3-7 shows an example of a triangle wave used in cyclic
voltammetry. In this example, the potential is cycled between -0.80 and
+0.60 V at a sweep rate of 0.1 V/s.
Doc. 065551-01 6/13
TIME (sec)
POTENTIAL
0.00
-
14.0
+
28.0
-
Figure 3-6. Waveform Screen
or
Select
buttons to find available potentials.
3 • Operation and Maintenance
screen (press
WAVEFORM
SAVE
(V)
0.80
0.60
0.80
,
).
Menu
4
3-13
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