Overview Of Optimization Parameters; Data Collection Rate And Filter Constant - Thermo Scientific VH-D20 Operating Manual

6 • Operation

6.10.2 Overview of Optimization Parameters

6.10.3 Data Collection Rate and Filter Constant

Data Collection Rate
Page 108
The following table serves as an overview of parameters that influence
the performance of the detector during data acquisition.
Parameter
Filter constant
Evaporation temperature
Power function value
Data collection rate
For further information about the parameters, refer to the Chromeleon
Help.
The Chromeleon software automatically calculates the best data
collection rate and filter constant, based on the value you enter for the
peak width in the Instrument Method Wizard.
If you want to select a different data collection rate and filter constant,
note the guidelines below.
The data collection rate is the number of data points per second (Hz)
that the Chromeleon software collects from the detector and stores as
raw data.
When you select a data collection rate, observe the following guidelines:
• In general, each peak should be defined by at least 20 data points.
For chromatograms with co-eluting peaks or low signal-to-noise
ratios, 40 data points per peak are recommended.
• If the data collection rate is too low, the start points, maxima, and
end points of peaks will not be determined accurately.
• If the data collection rate is too high, data files may need more disk
space and post-run analyses may require more processing time.
• If all peaks are relatively wide, select a lower data collection rate (for
example, 1.0 Hz). This saves disk space and allows for a faster display
of data in the Chromeleon software.
• If any peaks of interest are less than a few seconds, select a higher
data collection rate (10.0 Hz, for example).
• 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. See below.
Affects
Sensitivity, baseline noise
Baseline noise, background current
Linear range
Peak resolution, disk space, possibly baseline noise
Charged Aerosol Detectors (VH-D20, VF-D20)
Operating Manual