2.4.1 Model Development for Principal Component Analysis
MVA routines, including Principal Component Analysis (PCA), were applied
to the vibrational spectra acquired for each sample. The models were
created using The Unscrambler ® X 2018 CAMO Software (0349 Oslo, Norway)
version 10.5.1. Using OriginPro 8.6.0 (Northampton, MA, USA), Spectral
analysis for unprocessed raw data was made. Several pre-processing
methods were applied to the raw data. Standard normal variate (SNV),
Multiplicative scatter correction (MSC), Savitzky-Golay first derivative
(SG1), and Savitzky-Golay second derivative (SG2). These processing
methods were applied to each data set, including combinations to
separate the classes.