This Information Applies To: Agilent Fluorescence Detectors (FLD)
Issue
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.
Resolution
Excitation or Emission wavelength changes are programmed using a time table in the acquisition method (See Figure 1).
Figure 1. FLD time table in the acquisition method
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).
Figure 2. Selecting the Free baseline behavior option in the Special Setpoints tab of the FLD method page
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).
Figure 3. Blank injection demonstrating the effect of both the Append and Free settings on FLD Baseline behavior
 |
Learn how to effectively operate your Agilent 1260 LC system with OpenLab CDS:
Agilent 1260 LC System with OpenLab CDS eLearning path available from Agilent education |
