Mastic resin analysis

Despite the complexity of the chemical composition of the resinous materials, in a few minutes such techniques provide a mass spectral fingerprint, which highlights the compounds that are the main components in the sample. They avoid any sampling treatment before analysis. They have thus enabled diterpenoid resinous materials from Coniferae, and several triterpenoid materials to be clearly identified. In particular, the DE-MS technique is able to distinguish between different triterpenoid materials such as mastic resin, frankincense resin and birch bark tar. In fact, using PCA on DE-MS mass... 

Feller, K.L., Dammar and mastic infrared analysis. Science, 120 1069-1070 (1954). Shedrinsky, A.M., D. Grimaldi, T.R Wampler, and N.S. Baer, Amber and copal pyrolysis gas chromatographic (PyGC) studies of prevenance, Wiener Berichte fiber Naturwissenschaft in der Kunst, 6niS (1989/90/91), pp. 37—62. van Aarssen, B.G.K., J.W. de Leeuw, and B. Horsfield, A comparative study of three different pyrolysis methods used to characterize a biopolymer isolated from fossil and extant dammar resins, J. Anal. Appl. PyroL, 20 125-139 (1991). 

The assessment of the origin of terpenic resins by GC7MS is generally based on the qualitative recognition of specific molecular biomarkers that are normally specific for the genus [1,2,8,27,81-86]. Figures 36.8-36.10 illustrate the mass spectra of several biomarkers of mastic resin, frankincence resin, and birch bark tar, respectively. The GC/MS analysis of di- and triterpenoids requires the extraction and derivatization of... 

The first online TLC-MS attempt in the field of triterpenoids was done only in 2005 in the study of the photo-oxidation of natural di- and triterpenoid resins used as paint varnishes [10], The resinous samples were applied onto a cellulose-coated TLC plate, which afterward was subjected to direct MALDI-TOF-MS analysis without any development. The plates were only sprayed with a saturated ethanol solution of 2,5-dihydroxybenzoic acid as matrix to assist the ionization of compounds. Triterpenoids were observed as protonated molecules or as sodium clusters. Dammaradienone, dammaradienol, nor-a-amyrone, and dammarenolic, oleanonic, and ursonic acid were detected in dammar resin moronic acid, masticadienonic acid, and 3-0-acetyl-3-epi(iso)masticadienonic acid were found in mastic resin and diterpenoid abietane and pimarane acids were present in colophony. The induced aging process produced oxidized triterpenoids, which were observed in the MS spectra... 

In addition to GC/MS, high performance liquid chromatography (HPLC/MS) has been used to analyse natural resins in ancient samples, particularly for paint varnishes containing mastic and dammar resins [34]. A partial limitation of chromatographic techniques is that they do not permit the analysis of the polymeric fraction or insoluble fraction that may be present in the native resins or formed in the course of ageing. Techniques based on the direct introduction of the sample in the mass spectrometer such as direct temperature resolved mass spectrometry (DTMS), direct exposure mass spectrometry (DE-MS) and direct inlet mass spectrometry (DI-MS), and on analytical pyrolysis (Py-GC/MS), have been employed as complementary techniques to obtain preliminary information on the... 

Analysis of ebonite is more difficult than that of ordinary vulcanised rubber, as it is less readily attacked by solvents the sample for analysis should be finely powdered. The determinations of moisture, ash, sulphur, etc., are made as in manufactured rubber the extraction with acetone should be prolonged, sometimes to 1-2 days, to be complete. The residue insoluble in acetone is extracted first with epichlorhydrin for 3 hours to remove resins insoluble, or almost so, in acetone (copal, mastic, amber) and then with pyridine as indicated for manufactured rubber next comes the treatment with alcoholic potash to dissolve any brown factis present. The residue from this last treatment comprises the pure rubber, the sulphur combined therewith and the mineral matter in one part of it the ash and the sulphur of the ash are determined, and in another the total sulphur, the sulphur united with the rubber being obtained by difference the pure rubber is then calculated by difference. 

Comparison of the results of analysis of fresh and aged materials can lead to very different conclusions. For example, in the case of dammar and mastic, it is very easy to distinguish between the fresh samples of these resins, but after extensive artificial aging, dammar will retain its characteristic profile while mastic can give a completely unrecognizable one. °... 

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