BUCHI NIRCal - Manual (Page 37)

Tutorials
NIRCal 5.5 Manual, Version A 37
Suggested wavenumber range for NIRFlex N-500 with measuring options

Solids and Liquids: 4'000-10'000 cm
-1
;

Fiber Optics: 4'500-10'000 cm
-1
.

Solids with Tablet Accessory: 6'000-11'520 cm
-1
.
The calibration wavelengths define the spectrum range where the mathematical algorithms is applied.
Suggested selection: use all measured wavenumber in the first calculation, otherwise see Loop 2.
Link
Wavelength selection
2.2.6 Selecting the Calibration Properties
The calibration property is the parameter, that is required to determinate in the application. The
mathematical algorithm will be applied for the selected property values
Suggested selection: create separate calibration for each parameter - single property calibrations:
only one quantitative property is selected in each calibration.
NOTE
Quantitative calibration with several properties can not be stored to the Database, because it can not
be used in the application.
Link
Calibration property selection
2.2.7 Applying Data Pretreatments
Data pretreatments are used to eliminate non important effects or to enlarge minor effects of the
measurements.
Suggested selection: perform the first calculation without pretreatment, using the spectra as they have
been measured. The first step to optimize the calibration is to add and change the pretreatments.
Link:
Pretreatment selection
2.2.8 Performing a calibration (calculation)
After selecting the spectra (C-Set and V-Set spectra), the wavelength range (calibration wavelength)
and the properties (calibration properties), the chemometric parameters (principal components,
scores, residuals, etc) will be calculated.
For the calculation of PCR or PLS, the software uses only the spectra selected into the C-Set referring
to the cali
bration wavelength and the choice of the data pretreatment’s. The spectra of the V-Set will
only be used to prove and judge the calibration
An overview of the calculation can be obtained in the Menubar: View /
Overview .
The result of the calibration will depend on the selected number of primary and secondary principal
components. The first step is to decide on the numbers of PCs.
The calibration can be optimised manually or by using the
Calibration Wizard . Here the manual
selection criteria are described.