Thermo Scientific Dionex ICS-5000, Руководство оператора

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Dionex ICS-5000 Operator’s Manual
104
Doc. 065342-06 12/11
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
Figure 2-51 ).
With the example waveform shown in Figure 2-51 , the current is integrated
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.
Figure 2-51. Example Integrated Amperometry Waveform
Integration
Potential
(Volts)
Time (Seconds)
0.2 0 4 0.6
0.8
0.0
+0.35
-0.60
.
-0.10
+0.60
E3. Positive Cleaning Potential
E4. Negative Cleaning Potential
E1, E2 E3 E4
E1, E2. Detection Potentials