Advertisement
Point to point
Cubic spline
Thermo Fisher Scientific
Coefficients of the functions are solved with matrix calculations using
Gauss-Jordan elimination with backsubstitution algorithm, except for the
linear regression, where the linear least squares (LLS) method is used.
Roots of the polynomial, that is, the results", are calculated with an iterative
Laquerre's method. If more than one root is found in the calibration area,
the software produces a warning.
The point-to-point method connects the adjacent response-concentrations
coordinates, that is, the calibration points, together using a straight line (see
the equation below), which is different for each of the intervals. The results
are calculated by first searching for the correct interval and then using the
corresponding equation. The minimum number of calibrators for this fit
type is two.
y
= a
+ b
x
i
i
i
i
Extrapolation is not available for the point-to-point fit type. Only the means
of the measured calibrator replicates are used in the calculations. The
replicates are visible in the graph but they are not used in calculations.
This method is a smoothed point-to-point method where the adjacent
calibration points are connected together using cubic polynomials (see the
equation below) and optimizing the connecting points as smoothly as
possible to avoid sharp angles. The results are calculated by first searching
for the correct interval and then using a bisectional method to find the
answer from the corresponding equation. The minimum number of
calibrators for this fit type is three.
Note If you want to create several calibrators with the same
concentration, it is recommended to create one calibrator and then
create an appropriate number of replicates of the calibrator by using
the Fill Wizard and the No. of replicates setting. Otherwise the
cubic spline as a fit type in the quantitative curve fit calculation
will not process correctly.
2
y
= a
+ b
x
+ c
x
+ d
i
i
i
i
i
i
Thermo Scientific SkanIt
3
x
i
i
®
Software for Varioskan
Data Processing Parameters
Quantitative curve fit
®
User Manual
157
Hide quick links:
Advertisement
