LAUSR

Abstract In this work, an efficient analytical method based on headspace solid phase microextraction (HS-SPME) and multidimensional gas chromatography coupled with simultaneous quadrupole time-of-flight mass spectrometry and flame ionization detection (MDGC-QTOFMS/FID) was established to analyze volatile terpenoids of Rhododendron. The HS-SPME method were optimized for the best extraction efficiency by using divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibers at 70 °C equilibration temperature for 20 min, and extracted for 15 min. A total of 34 volatile terpenoid compounds were identified by NIST mass spectral match, and confirmed by accurate mass and retention index (RI). Quantitative analysis was performed with an internal standard (IS) 1,4-cineole. The relative standard deviations (RSD) of most identified compounds were d -limonene (average 2781.69 μg/kg), followed by p-cymene (average 254.52 μg/kg), linalool (average 224.40 μg/kg), 6-methyl-5-hepten-2-one (average 150.39 μg/kg) and α-terpineol (average 140.17 μg/kg). Additionally, principal component analysis (PCA) was applied to study the detailed differences in terpenoid concentrations in different parts of Rhododendron species.