Chemometric resolution techniques combined with GC-MS to enhance determination of the volatile chemical constituents of bay leaves
The 71 constituents of essential oil (EO) of bay leaves were identified with gas chromatography-mass spectrometry (GC-MS) by applying a similarity search between the obtained mass spectra and database. This number was increased to 131 constituents with the help of different chemometric resolution techniques. Multivariate curve resolution-alternating least squares (MCR-ALS) is used to obtain pure chromatograms and mass spectra for the constituents present in each overlapping/embedded peaks cluster as well as their relative concentrations. Other chemometric methods such as simple to use interactive self-modeling mixture analysis (SIMPLISMA), morphological score (MS) and Fixed Size Moving Window Evolving Factor Analysis (FSMWEFA) were used to determine the number of constituents, pure variables, zero concentration and selective regions. The most important constituents of the Iranian bay leaves are linalool (12.31%), 1,8-cineole (11.38%), α-terpineol acetate (7.71%), eugenol methyl ether (6.87%) and α-phellandrene (4.30%). Despite previous studies, chemometric resolution techniques were implemented as a necessary step for the comprehensive analysis of the volatile constituents of bay leaves.