Chromate 4300 - 4.2.8 Dose Response Mode; 4.2.9 Cubic Spline Mode

28 ChroMate™ Operator’s Manual Doc. 4300 Rev. E
4.2.8 Dose Response Mode
Dose Response:
Description:
Dose Response mode uses non-linear
regression (Levenberg-Marquardt method)
to fit the calibration curve to a four-
parameter logistic equation defined by:
Y = Bottom + (Top-Bottom) / (1 + 10 ^
((LogEC50-X) * HillSlope)) yielding a
sigmoid curve.
The parameter “Bottom” is the absorbance
value at the bottom of the plateau, “Top” is
the absorbance value at the top of the
plateau, and LogEC50 is the concentration
value halfway between the “Bottom” and
“Top”.
The parameter HillSlope describes the
steepness of the curve. When the Hillslope
is less than 1.0 the curve is shallower, when
the Hillslope is greater than 1.0 the curve is
steeper.
4.2.9 Cubic Spline Mode
Cubic Spline:
Description:
Cubic Spline mode accepts a number of
calibrators and calculates concentrations
based on the Cubic Spline (Constrained)
calibration curve.
The resulting calibrator curve is a smooth
curve connecting the calibrator points,
which may be entered in ascending or
descending order of absorbance. A
constraining algorithm is applied to prevent
curve overshoot.