Response Time And Data Collection Rate - Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual

UltiMate 3000 Series:
Fluorescence Detectors FLD-3100 and FLD-3400RS
• You can manually select the filter wavelength. Available filters are 280 nm, 370 nm,
435 nm or 530 nm. The selected emission wavelength must not be more than 15 nm
below the filter wavelength. In special situations (for example, if the emission
wavelength is near the cut-off wavelength of a filter), setting the filter manually may
provide better results than the Auto setting.
If you select Open, the filter wheel remains in an open position. Use this setting if you
want to measure with an emission wavelength between 220 nm and 280 nm.
Manually select the filter wheel position, for example, in combination with the Zero Order
Mode. The emission monochromator opens and the emitted light is measured over the entire
wavelength range. Use the cut-off filter to suppress light below the wavelength you are
interested in. Note that this setting usually requires a lower Sensitivity setting due to the stray
light and auto fluorescence of the eluent (the entire spectral range is recorded).
You can select the filter wheel setting for all channels directly in the Program Wizard
(→ page 68).
For further information about selecting the filter wheel setting, refer to the Fluorescence
Method Development Handbook that is shipped with the detector.

5.7.4 Response Time and Data Collection Rate

Tip: In Multi-Channel Mode, you cannot directly select the Response Time and
Data Collection Rate, as these parameters are determined automatically
(→ page 87).
The response time is a measure of how quickly the detector responds to a change in signal.
The data collection rate is the number of data points per second (Hz) that Chromeleon
collects from the detector and stores as raw data.
The Program Wizard in Chromeleon automatically calculates the appropriate response time
and data collection rate, based on the value you enter for the peak width at half-height
(→ Fig. 31, page 68). If you want to select a different response time and data collection rate,
note the following guidelines:
Response time
• Select a response that is about 1/3 of the peak width at half-height of the narrowest peak
of interest. A longer response time allows more averaging of the signal and results in less
short-term noise.
• However, if the selected response time is too long, this can result in reduced peak heights
and asymmetrical peak shapes. Peaks that elute shortly after each other may not be
separated properly. When set correctly, the response time significantly reduces baseline
noise, but reduces peak height only slightly.
Page 86 Operating Instructions