A multivariate analysis of the Raman spectrum is performed for dimensionality reduction of all experimental Raman spectra. Inherent features of the investigated samples are extracted from the data set using NMF as implemented in the Python package "Scikit-learn" . It decomposes every measured sample spectrum (𝑐 ) into a specified number 𝑚 of components (loading plots, 𝑥 ) and their corresponding weighting factors (scores, 𝑤 ) . The original data is then represented by the following matrix equation :