BUCHI NIRCal - Manual (Page 34)

NIRCal 5.5 Software Manual
34 NIRCal 5.5 Manual, Version A
2.1.10 Secondary Principal Components
The secondary or calibration PCs are used for the separation of the different substances and are
responsible for the tolerance radii calculation. The number of secondary PCs is limited by the
number of primary PCs.
Recommended graphics for the selection:

2- and 3-D Scores plots,

Scores against Spectra and

Property Box Radii.
These plots are part of the Overview-Plot.
Suggested selection: use just as many secondary PCs as necessary to get a selective calibration.
Link:
Secondary PCs
Adjust the desired number of secondary PCs.
Link:
Adjusting Secondary PCs
Setting the Radii Formula and Radii Blow up Limit
Calculation of the tolerances can be made with two different formulas and with different blow up limits .
NOTE
It may be necessary to reduce the blow up limit for different chemical substances, when Formula
1 is used in order to increase the sensitivity of the calibration.
Edit the value for Radii Blow Up Limits or Formula.
NOTE
After each new selection a recalculation should be performed again.
2.1.11 Judging the Calibration
In a good calibration, the different properties should appear as a separated and ideally compact
cluster. The proper clusters are visible in the Overview.
For judging the quality of calibration the following criteria are used:

Cluster per Property: should be one, so only one cluster for each property:

Spectra Residuals too big: zero (no residual outlier);

Property Residuum: should be zero which means, that all spectra are in the right cluster;
The 2nd column of the Overview contains important control windows.

Q-Value : should be as close to 1 as possible;

Calibration Protocol : show the important adjustments and result of the calibration

Prediction Protocol show possible wrong identification for substance spectra not involved in
the calibration
After several calibration optimizations and running the automatic calibration wizard, there will be
several calibrations in the project. Sort the calibrations with a click on the Name or Q-Value.
NOTE
Keep only the best calibration and delete all others.
2.1.12 Save Calibration - Lifecycle
Save the project and the calibrations to the database. Only approved calibrations according to
Lifecycle will be available in the NIRWare Application Designer. See
Calibration handling for further
details.