Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 83

Emission Scan
The wavelength on the excitation monochromator is kept constant, while the emission
monochromator scans a wavelength range. The result is an emission spectrum of the
sample.
Synchro Scan
A user-defined excitation wavelength range is scanned, while the emission wavelength is
scanned synchronously with a fixed distance. This allows you to determine rough values
for the excitation and emission wavelengths of all substances in a first scan. However, the
optimum excitation and emission wavelengths can be determined by using excitations
scans and emission scans only.
To perform a 2D spectra scan
Spectra scanning can be performed manually (as described below) or by using a program.
For additional information and more options for spectrum scans as well as program
examples, see the Chromeleon Help.
Tips: During the scan process, no other commands can be sent to the fluorescence
detector.
The duration of the scan process depends on the range to be scanned and the
selected scan speed.
Before each scan, select a detector sensitivity, using the ScanSensitivity
command (→ page 81).
Artefacts may occur when scanning near extreme changes in the spectrum
(which frequently occur near the excitation wavelength), for example, when
scanning the Raman emission spectrum of water near the excitation of 350 nm.
In this case, select a greater distance between the wavelength scan range and
the edge. For the Raman emission scan, for example, select a start wavelength
of 385 nm.
Manual spectra scans are supported under Chromeleon 6.80, but are currently
not supported under Chromeleon 7.1 or later.
Complete the following steps to record an excitation spectrum:
1. Open the Commands dialog box for the detector. Under ScanStartExWavelength,
enter the first wavelength of the range to be scanned and the last wavelength under
ScanEndExWavelength. Select an emission wavelength (ScanStartEmWavelength)
and a scan speed (ScanSpeed).
2. Stop the pump flow (Flow=0) or set it to a very low flow rate.
3. Execute the ScanExcitation command.
Operating Instructions
Fluorescence Detectors FLD-3100 and FLD-3400RS
UltiMate 3000 Series:
Page 75