GE HEALTHCARE Biacore T100, Handbook

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7 Data presentation tools
7.2 Plot items
130
Biacore T100 Software Handbook BR-1006-48 Edition AE
7.2.5 Adjusting plots for controls
Plots can be adjusted for systematic changes in response during the course of
the assay, such as progressive loss of binding capacity resulting from harsh
regeneration conditions. Adjustment is calculated from the response values
obtained for control samples analyzed at intervals during the assay.
Adjustment for controls cannot be applied to plots of molecular weight-
adjusted response values or to plots of one report point against another.
To apply this adjustment, choose Adjustment for controls from the Tools menu
in the plot window. Check Use adjustment for controls and select the sample to
use as a positive control. You can also select a sample for the negative control.
Select whether the adjustment should be made using a linear or polynomial
(second degree) fitting function. The display panels in the dialog show a plot of
the response against cycle number before and after adjustment. Click
OK to
apply the adjustment.
Adjustment normalizes the sample responses relative to the positive and
negative control levels as follows:
• Curves are fitted to the control sample responses for positive and (if used)
negative controls. The
Linear option fits the points to a function with the
form y = ax + b (where a and b are constants). Polynomial fits the points
to a second-degree function with the form y = ax
2
+ bx + c (where a , b and
c are constants). If no sample is chosen as a negative control, 0 RU is used
as the negative control response.
• The fitted line(s) are transformed to straight horizontal lines with values
100 for the positive control and 0 for the negative control.