Pine resin, analysis

Parallel analyses by IR, thin-layer chromatography (TLC), and gas chromatography-mass spectrometry (GC-MS) of organic remains adhering to shards of ancient amphoras excavated in the harbor of Carthage (Tunisia) identified these remains as pine pitches. Capillary GC of methylated acid fractions showed abietic acid, dehydroabietic acid, and 7-ketodehydroabietic acid as the principal components. Two-dimensional TLC of untreated ether extracts revealed abietic acid in 12 of 31 samples and dehydroabietic acid in 26 of 31 samples. IR spectra of solid, raw samples indicated the presence of isopropyl groups, characteristic of the abietane skeleton, in 80% of the samples. Rapid and convenient analysis by TLC and IR was, in most cases, sufficient to identify pine resin products even after extensive pyrolytic and oxidative degradation. 

GC (with or without identification of constituents by MS) remains the most precise, quantitative method for the detailed analysis of resinous remains and the choice when a relatively small number of samples must be studied in depth. It provides information about the method of preparation, that is, about early resin and pitch technology. The analyses reported in this chapter and elsewhere (20) have been the impetus for current work in this laboratory on replication of ancient pitch manufacturing methods and identification of the types of pine resins that were used. 

Physical Form. Volatile liquid, colorless or yellow, which is a mixture of natural substances obtained ftom resinous exudates or resinous wood ftom living or dead coniferous trees, especially pine trees. The chemical composition can vary with the source and method of derivation, but a typical analysis of turpentine is a-pinene, 82.5% camphene, 8.7% (3-pinene, 2.1% unidentified natural turpenes, 6.8%. 

The combined genomics and chemical approaches to plant terpenoid research are not restricted to the few plant species for which more or less complete genome sequences are now available. The discovery of many of the genes and enzymes for the formation of terpenoids such as menthol and related monoter-penes in peppermint Mentha x piperita) (15), artemisinin in Artemisia annua (16), Taxol in the yew tree (Taxus) (17), or conifer diterpene resin acids in species of spmce (Picea ) and pine (Pinus) (18) have been possible on the foundation of highly specialized efforts of EST and full-length cDNA sequencing combined with characterization of recombinant enzymes and analysis of the terpenoid metabolome of the target plant species. 

In view of the wide application of Py—GC in industry and research, the development of techniques and equipment for automatic analysis by this method is of great practical interest. An automatic Py—GC system was developed by Coulter and Thompson [69] for Curie-type cells with a filament for specific application in the tyre industry. A typical analysis involves the identification and determination of polymers in a tyre material sample. The material of a tyre is essentially a mixture of polymers, most often natural rubber (polyisoprene), synthetic polyisoprene, polybutadiene and butadiene-styrene copolymer. A tube is normally made of a material based on butyl rubber and a copolymer of isobutylene with small amounts of isoprene. In addition to the above ingredients, the material contains another ten to twelve, such as sulphur, zinc oxide, carbon black, mineral oil, pine pitch, resins, antioxidants, accelerators and stearic acid. In analysing very small samples of the tyre material, the chemist must usually answer the following question on the basis of which polymers is the tyre made and what is their ratio The problem is not made easier by the fact that cured rubber is not soluble in any solvent. 

The terpene resin exudates from the plant, as happens with other pine trees, as a result of the injuries provoked by insects, birds or men. It is a viscous liquid, composed of terpene products, which becomes hard in contact with air. The analysis of the Parana pine tree terpene resin shows moisture, 13,1% mucilaginous material, 39,7% rosin, 37,2% turpentine, 5,0% and miscellaneous, 5,7% ... 

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