Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 90

UltiMate 3000 Series:
Fluorescence Detectors FLD-3100 and FLD-3400RS
Fig. 35: Effects of the Sensitivity setting
Determining the optimum Sensitivity
Determine the optimum sensitivity in a separate sample run after you have determined the
optimum wavelengths (→ page 78). Use a sample (standard) with the maximum expected
concentration of the analytes and select a sensitivity at which a saturation is not expected
(for example; 1 or 2). If the peak heights of the individual peaks in a chromatogram differ,
you can improve the signal-to-noise ratio of the smaller peaks by switching the sensitivity
during the run. You can select the Sensitivity for all channels directly in the Program
Wizard (→ page 68).
With the FLD-3x00(RS), the intensity of the emission light (measured by the PMT) is
normalized with the intensity of excitation light through the sample (measured by the
reference diode). Therefore, the values (counts) that the emission channel displays cannot be
used for optimizing the sensitivity. In Fig. 35 the PMT is saturated at 63 million counts.
However, under different measuring conditions, the PMT may be saturated at a value of
100 million counts, for example.
Page 82 Operating Instructions