Thermo Scientific 074114, Operator'S Manual

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Dionex PDA Operator’s Manual
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Doc. 065378-01 1/12
Rise Time
Rise time is a measure of how quickly the Dionex PDA responds to a change in
signal. The selected rise time is applied to all data collected, as well as to both
analog and digital output. The Dionex PDA rise time settings are 0.05, 0.1, 0.2,
0.5, 1.0, 2.0 (default), or 5.0 seconds.
Select a rise time that is about 25% of the peak width at half-height of the
narrowest peak of interest. A longer rise time allows more averaging of the signal
and results in less short-term noise (see
Figure 3-5 ). However, a rise time that is
too long may result in reduced peak heights and asymmetric peak shapes. When
set correctly, the rise time significantly reduces baseline noise, but reduces peak
height only slightly.
Do not use a stainless steel flow cell with low pH solutions; these
solutions may cause corrosion, contamination, and metal leaching.
Figure 3-5. Effect of Rise Time on Baseline Noise
-0.0100
0.0000
0.0100
0.0250
0.00 1.00 2.00 3.00 4.00 5.00
mAU
min
WVL:254 nm
-0.0200
-0.0100
0.0000
0.0150
0.00 1.00 2.00 3.00 4.00 5.00
mAU
min
WVL:254 nm
Rise Time: 0.5 sec
Baseline Noise: 22
P
AU
Rise Time: 2.0 sec
Baseline Noise: 10
P
AU