Thermo Scientific Dionex ICS-5000 Operator's Manual page 120

Dionex ICS-5000 Operator's Manual
measured by integrating the current for a fixed time. Current integrated for a
fixed time is charge and the units are coulombs. At t2 and t3, positive and
negative cleaning pulses are added to the waveform. This waveform period
repeats until the end of data acquisition or until another waveform is
specified.
Integrated Pulsed Amperometric Detection
With integrated pulsed amperometric detection (IPAD), current is integrated
at two or more potentials (see
+0.60
+0.35
Potential
(Volts)
-0.10
-0.60
Figure 2-51. Example Integrated Amperometry Waveform
With the example waveform shown in
both while the potential is swept across the metal oxide formation wave and
also during the reverse sweep across the oxide reduction wave. This technique
minimizes baseline shift and the peak dips that can occur when an eluting
analyte's effect on oxide suppression is greater than the detector response
from the analyte.
As with pulsed amperometric detection, the waveform period repeats until the
end of data acquisition or until another waveform is specified.
104
Figure
Integration
.
0.0 0.2 0 4
Time (Seconds)
E1, E2
2-51).
0.6
0.8
E1, E2. Detection Potentials
E3. Positive Cleaning Potential
E3 E4
E4. Negative Cleaning Potential
Figure 2-51, the current is integrated
Doc. 065342-06 12/11