Thermo Scientific Corona Veo, Operating Manual

Page: 142 / 262

6 • Operation
Page 142 Charged Aerosol Detectors Corona Veo (RS) Operating Manual
6.7.3 Filter Constant
The filter constant is applied to the output current to electronically
reduce the baseline noise during the analysis.
When setting a filter constant, observe the following:
•
A small filter constant, such as 0.2 seconds, removes little baseline
noise.
•
A large filter constant, such as 10.0 seconds, smoothes the baseline
significantly.
• Consider also the filter constant when setting the data collection
rate. Set the two parameters together in order to optimize the
amount of data points collected, and reduce short-term noise, while
still maintaining peak height, symmetry, and resolution.
6.7.4 Evaporation Temperature
The temperature-controlled evaporation tube dries the aerosol droplets
that come from the spray chamber. The evaporation tube evaporates
the more volatile components in the droplets to produce dried particles
composed of non-volatile analyte and background residue.
The efficiency of the drying procedure depends on the set temperature.
Additional factors, such as the mobile phase composition, the pump flow
rate and the sample composition, also play an important role.
Note the following when selecting an evaporation temperature:
•
The default evaporation temperature is set to 35 °C.
•
When selecting a different evaporation temperature, observe the
evaporation temperature specification for the detector. See
section 9.1 Performance Specifications, page 236 .
•
Changes in the evaporation temperature affect the response of the
detector.
• When the temperature is changed, the evaporation tube requires
time to equilibrate. Wait approximately 30 minutes before you start
sample analysis to make sure that the detector is only ready for
analysis when the evaporation tube is equilibrated.