Bio-Rad EXQuest Spot Cutter - Manual (Page 534)

Appendix L. Techniques
L-9
Calibration Curve Problems
Find errant data points and their corresponding segments using the function Display
Segment Quan.
Above each sampling box will be displayed the average O.D. value within the box,
and just below the box will be displayed the corresponding DPM (or other specified
unit). This should tell you which sampling boxes correspond to errant data points on
the graph.
Usually, problems arise when a box straddles the boundary between two adjacent
segments or the density is very uneven within the segment due to bleeding from an
adjacent segment. These sorts of problems should be remedied by redoing the
sampling boxes.
Use the function Remove Segment to remove an errant sampling box.
Draw a new sampling box on the segment using Box Segment, as described above.
Place the new box carefully to avoid repeating the problem. For example, keep the
box away from segment boundaries. If the segment shows bleeding, place the
smallest box possible in an area of the segment with representative O.D. Try not to
sample blotchy areas.
Replot the calibration curve using the function Plot Calib. Curve.
If there is still a problem, you can opt not to include that particular segment in the
calculation of the calibration curve. Select De/Activate Segment and click on the
problem segment. The segment will still exist, so its counts in the corresponding
Calstrip Record do not need to be changed or deleted. However, the segment will not
be included in the calculation of the calibration curve.
If you change your mind and want to reinclude the segment, select De/Activate
Segment again and click on the segment. The segment will be reactivated and
included in calibration curve calculations.
L.1.e Repeat for Each Calstrip
If you have multiple film exposures of the same gel, repeat the steps outlined above
for each exposure. The calibration strip batch number for each film exposure of a