ThermoFisher Scientific Vanquish VC-D50, Operating Manual

Page: 113 / 188

6 • Operation
Fluorescence Detectors (VC-D50, VC-D51, VF-D50, VF-D51)
Operating Manual Page 113
wavelength is near the cut-off wavelength of a filter), setting the
filter manually may provide better results than the
Auto setting.
Note the following:
¨
The selected emission wavelength must not be more than 15 nm
below the filter wavelength.
¨
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 range 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).
For further information about selecting the filter wheel setting, refer to
the Fluorescence Method Development Handbook that is shipped with
the device.
6.9.6 PMT (only if second PMT is installed)
Detectors can be equipped with a second PMT for the near-infrared
region (up to 900 nm). If the PMT setting is set to
Auto , the detector
selects the suitable PMT for each measurement. As an alternative, you
can manually select which PMT should be used. Use PMT1 for
measurements in the UV/VIS region. Use PMT2 for measurements in the
infrared region.
TIP Always use the same PMT setting for calibration and quantification.
A calibration performed with PMT1 may not be valid for measurements
with PMT2.
6.9.7 Data Collection Rate and Response Time (Single-Channel Mode)
The Chromeleon software automatically calculates the best response
time, based on the value you enter for the data collection rate in the
Instrument Method Wizard. Note the guidelines below for selecting the
data collection rate. If you want to select a different response time, this
section also provides a few guidelines.