This Information Applies To: Agilent Fluorescence Detectors (FLD)
Sometimes it’s necessary to change FLD EX and EM wavelengths during a run since not all components will excite or emit at the same wavelengths. However, when the wavelength change is made, the detector will autozero which will cause the baseline to step up or down, making integration a challenging task.
Excitation or Emission wavelength changes are programmed using a time table in the acquisition method (See Figure 1).
By default, the baseline is set to Append. This setting will autozero the baseline each time a wavelength change occurs.
To avoid the autozero, Go to the detector setup screen, then Click to open the Special Setpoints tab. Under Miscellaneous, check the Free option. The baseline will no longer autozero after a wavelength change (see Figure 2).
To demonstrate the baseline effect, a blank run [no injection] was made using the timetable above with the Baseline behavior set to Append then to Free.
Figure 3 shows an example of a blank run (no injection).
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