Comprehensive 2D gas chromatography-time-of-flight mass spectrometry with 2D retention indices for analysis of volatile compounds in frankincense (Boswellia papyrifera).

Frankincense gum resin secreted from Boswellia papyrifera was analysed by comprehensive 2D gas chromatography hyphenated with accurate mass time-of-flight mass spectrometry (GC×GC-accTOFMS). Direct multiple injection experiments with stepwise isothermal temperature programming were then performed to construct isovolatility curves for reference alkane series in GC×GC. This provides access to calculation of second dimensional retention indices (2 I). More than 500 peaks were detected and 220 compounds mainly comprising monoterpenes, sesquiterpenes, diterpenes and oxygenated forms of these compounds were identified according to their 1 I, 2 I and accurate mass data. The study demonstrates the capability of GC×GC-accTOFMS with retention data on two separate column phases, as an approach for improved component identification. A greater number of identified and/or tentatively identified terpenoids in this traditional Chinese medicine allow for a more comprehensive coverage of the volatile composition of frankincense.