Derivatives, 6 derivatives – BUCHI NIRCal User Manual
Page 107
Chemometrics
NIRCal 5.5 Manual, Version A
107
Formula:
Type
This pretreatment is not depending on the calibration wavelengths.
NOTE
The information loss can be very high.
Average Savitzky-Golay 9 points
Savitzky-Golay Smoothing (=zero-order derivative), 9 points, cubic
Type
This pretreatment is not depending on the calibration wavelengths.
3.5.6 Derivatives
Derivatives
A derivative is used to reduce baseline effects and to increase smaller absorption peaks (shoulder
effect). The first derivative will eliminate a linear ordinate offset. The second derivative will eliminate a
sloping baseline.
NOTE
When using a derivative the signal-to-noise ratio will decrease. Therefore often it will be necessary to
combine it with smoothing.
Many derivative calculations are based on polynom fitting, therefore because of the mathematics
involved, some smoothing will be applied anyway.