Gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) were used to compare between the essential oil components from needles of Pinus armandii Franch versus P. tabulaeformis Carr., growing on the same site at Taibai Mountain, China. Under optimum extraction and analysis conditions, 65 and 66 constituents each were identified in P. armandii and P. tabulaeformis, which accounted for 87.9% and 87.1%, respectively, of their oils. Based on their terpene compositions, we concluded that these species belong to a high-caryophyllene chemotype, with sesquiterpenes comprising 54.4% to 54.8% of the total contents. We also determined minor qualitative and major quantitative variations in some compounds. Compared with that from P. tabulaeformis, P. armandii oil had more γ-muurolene (7.5%), terpinolene (5.8%), and longifolene (5.7%). In contrast, α-pinene (8.6%) and caryophyllene oxide (7.4%) were the dominant compounds in P. tabulaeformis.
Comparative analysis of protein extraction methods for the identification of seafood-borne pathogenic and spoilage bacteria by MALDI-TOF mass spectrometry
