Application of Polyamide Nanofibers, SPME/GC-MS, and Chemometrics for Comprehensive Analysis of Volatiles in Thymus vulgaris L. and Thymus serpyllum L

Garden thyme (Thymus vulgaris L.) and wild thyme (Thymus serpyllum L.) volatile components have been extracted using solid-phase microextraction (SPME) with polyamide nanofibers, prepared by electrospun technique. The polyamide nanofibers were used for SPME because of its high porosity and high surface to volume ratio. The homogeneity and porosity of the prepared polyamide nanofibers was investigated by scanning electron microscopy having diameters of 50–100 nm. Gas chromatography-mass spectrometry (GC-MS) together with chemometrics was implemented to resolve the co-eluted components and improve analytical performance. After applying multivariate curve resolution-alternating least squares (MCR-ALS) to resolve the overlapped and embedded peak clusters, 32 and 43 components have been identified in garden and wild thyme, respectively. Furthermore, principal component analysis (PCA) was implemented to characterize hidden structure and to identify volatiles differentiating between garden and wild thyme. The proposed strategy of SPME/GC-MS together with chemometrics may be useful for comprehensive and rapid analysis of complex natural extracts such as garden and wild thyme.