DAD 6.1L/DAD 2.1L/MWD 2.1L user manual V6700, version 3.2
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Optimizing the Detector
Warm Up Time
The recommended warm-up time for the detectors is 30 minutes. This rec-
ommendation is applicable after turning the detector on as well as and after
turning the lamp/s on.
Selecting the Flow Cell
Several different flow cells are available for the detector (see “Flow Cells” on
page 52). Note that the detector is shipped with a test cell. A flow cell must
be ordered separately.
Signal sensitivity, peak broadening and response can all be affected by the
choice of flow cell. Volume, path length as well as wetted parts, required
pressure range, flow cell connection, and remote operation are further fac-
tors that need considering when selecting a flow cell.
Flow Cell Volume
Depending on your instrument setup, column and sample(s), one flow cell
volume may be more appropriate that another. If the volume is too large,
two adjacent peaks may get mixed in the cell. If the volume is too small, the
noise may be higher and the signal may be too small due to less light reach-
ing the photodiodes.
Ideal flow cell volume therefore is a compromise between peak broadening
and sensitivity (see figure 23).
A good rule of thumb is that the flow cell volume should not be more than
1/3 of the peak volume of your separated sample. To determine the volume
of your peaks, take the peak width as reported in the integration results,
multiply it by the flow rate and divide it by 3.
Fig. 22
cold start temperature profile
Fig. 23
volume comparison
