Operational Modes Of The Detector; Single-Channel Mode; Multi-Channel Mode (Fld-3400Rs Only) - Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual

5.6 Operational Modes of the Detector

5.6.1 Single-Channel Mode

A fluorescence detector is usually operated in single-channel mode, that is, a single
excitation/emission wavelength pair is measured. As this mode provides the highest
possible data rates and best signal-to-noise ratio, always use the single-channel mode for
very small peaks.

5.6.2 Multi-Channel Mode (FLD-3400RS Only)

In multi-channel mode, both monochromators quickly switch between the selected
wavelengths. A single analysis is sufficient to measure several channels. The FLD-3400RS
can acquire up to four wavelength pairs simultaneously. However, note that:
• Each additional channel increases the time that the detector requires to set the grating
positions, reduces maximum possible data collection rate and leads to an increased
baseline noise.
• Switching permanently between the wavelengths can lead to wear in the long tearm. The
multi-channel mode is therefore only recommended for method development, but not for
continuous routine operation.
• As an alternative, you can switch the wavelengths as often as required in a data channel
in Chromeleon. Thus, you can switch the excitation and emission wavelength,
respectively, and, if required, the sensitivity, the emission filter and the PMT. For further
information, see section 5.7 (→ page 77) or the Fluorescence Method Development
Handbook that is shipped with the detector.
Tips: In Multi-Channel Mode, you cannot directly select the Response Time and
Data Collection Rate, as these parameters are determined automatically
(→ page 87) and adjusted accordingly when wavelengths are switched during
the measurement.
In Multi-Channel Mode, the selected lamp mode is always HighPower.
Manual acquisition from the Commands dialog box is only supported for one
channel.
Operating Instructions
Fluorescence Detectors FLD-3100 and FLD-3400RS
UltiMate 3000 Series:
Page 73