Analysis of diterpenic compounds by GC-MS/MS: contribution to the identification of main conifer resins.

The three principal types of molecules composing diterpenic resins are the abietanes, pimaranes and labdanes. The study of their fragmentation was performed by gas chromatography coupled to an ion trap mass spectrometer, on standards and resins used in paint varnishes: colophony and sandarac. We found that the general fragmentation pattern was mostly governed by the location of the double bonds on the different cycles and the presence of functional groups, and not by the nature of the C13 group in the case of abietanes and pimaranes. As for the labdanes, the loss of their alkyl chain is very specific. This study develops an analytical strategy using tandem mass spectrometry (MS/MS) experiments to validate the proposed mechanisms of fragmentation and to find the ions of interest for the identification of diterpenic molecules. Graphical Abstract Analysis of diterpenic compounds by GC-MS/MS.

Analytical investigation of styrax and benzoin balsams by HPLC- PAD-fluorimetry and GC-MS.

An HPLC and GC study has been conducted on the aromatic oleoresins styrax and benzoin produced by several American, Mediterranean and East-Asian trees, and widely used in ancient civilisations for their therapeutic and odoriferous properties. Initial experiments were performed by HPLC-PAD-fluorimetry for the analysis of several aromatic components, and then completed by GC-MS for the characterisation of both aromatic and triterpenic derivatives. In this work, it was crucial to isolate from fresh natural exudates, and to characterise by two-dimensional NMR, some of the major constituents in order to extend the standard molecular pool prior to chromatographic identifications. This study reveals coniferyl benzoate as an excellent distinctive fluorescent biomarker of Siam benzoin substrate. It also confirms that fluorimetric-coupled detection is a powerful analytical tool for the identification of compounds in Hamamelidaceae extracts that are almost undetectable by UV. GC-MS was successfully applied to the determination of the botanical origin of Sumatra benzoin, and to the identification of lupeol [3beta-lup-20(29)-en-3-ol] for the first time in such balsam-type materials.

Analysis of frankincense in archaeological samples by gas chromatography-mass spectrometry.

Four archaeological samples, unearthed from Qana in Yemen were analysed by analytical technique, currently applied in the field of petroleum geochemistry, and by gas chromatography coupled with a mass spectrometer (GC-MS). Sample no 1286 comes from a burned warehouse and samples no 964, 963 and 962 from the central sanctuary. These specimens were probably exposed to a heating source. In each case olibanum resin was identified according to the presence of their chemical markers corresponding to alpha- , beta-boswellic and lupeolic acids (3alpha-hydroxy-olean-12-en-24-oic, 3alpha-hydroxy-urs-12-en-24-oic and 3alpha-hydroxy-lup-20(29)en-24-oic acids) and their respective O-acetyled derivatives (3alpha- O-acetyl-olean-12-en-24-oic, 3alpha-O-acetyl-urs-12-en-24-oic and 3-O-acetyl-lup-20(29)-en-24-oic acids). Concerning the thermal degradation state of samples, the GC-MS results are in agreement with the geochemical ones. Sample no 1286 and 964 correspond to ageing incense which has not undergone any heating action and are consequently relatively well preserved. Lastly, samples no 963 and 962 are thermally degraded resins and their gross composition data permits to conclude that sample no 963 is only partially burnt while sample no 962 has been much more degraded.