Chemometrics-based vibrational spectroscopy for Juglandis semen extracts investigation

In this study, the chemical composition of Juglandis semen extracts obtained by different extraction solvents and methods were determined by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The multivariate analyses, principal component analysis and hierarchical cluster analysis of the FTIR and Raman spectral datasets, were performed to determine the differences in the chemical composition according to the solvent (e.g., mixture of water with alcohol, glycerole, and propylene glycol) and the extraction method (i.e., ultrasound-assisted extraction, rapid pressurized extraction, and subcritical fluid extraction). The obtained results reveal that the J. semen extracts with water-alcohol solvent have equivalent chemical composition. A well-defined differentiation based on extraction method could not be highlighted. Based on FTIR data compilation, it can be observed that a first classification can be made based on the solvent, acidic or basic, used for extraction methods (except subcritical fluid extraction - SFE, clustering is clearly assigned by the solvent). Multivariate analysis on FTIR and Raman spectral data was able to differentiate SFE extract as a unique cluster, which means HFC134a solvent allowed a specific extraction (from organic constituents' point of view) due to the selected conditions of extraction method.