Antec Scientific ROXY Exceed, User Manual, Page: 81 / 126

Chapter 7 Optimization of working potential 81
In the example below a half scan is shown at a flow rate of 10 µL/min of a
20 µM Serotonin (5-HT) standard in mobile phase.
Fig. 40. Scan (cycle: half) of a 20 µM Serotonin in mobile phase at a
glassy carbon working electrode. Scan speed 20 mV/s.
The following procedure is advised to record scanning voltammogram of
analytes:
•
Use a voltammetry set-up as shown in figure 48 (preferably) in
combination with the Dialogue Elite software and a syringe pump
for direct infusion of analyte in the flow cell.
•
Prepare a solution of the pure compound dissolved in (preferably)
the HPLC buffer with a concentration in the range of 10-100 µM.
•
Set the lower (E1) and upper potential (E2), the scan rate (Spd),
range and scan cycle
in the ‘SCAN SETUP’ menu or under the
If Dialogue is not used, connect an A/D converter to the analog output
of the potentiostat to record the cell current. Set the A/D converter
sampling rate to 1 Hz. This is the same frequency as the voltage steps
during the scan. If a higher sampling frequency is chosen a typical
stepwise pattern may appear. Note that with such set-
up only ‘I versus
t’ curves can be obtained.