Identification of archaeological and recent wood tar pitches using gas chromatography/mass spectrometry and pattern recognition

Abstract

An analytical method has been developed for the assignment of recent and archaeological wood tar pitches to the species of trees used for their preparation. It Incorporates the prepurlflcatlon by Kugelrohr distillation and solid-phase extraction followed by gas chromatography/mass spectrometry analysis. Distribution patterns of volatile, thermostable triterpenoids and steroids characterizing the biological origin of the pitches are evaluated by principal component analysis (PCA) and discriminant component analysis (DCA) of the data. Quantities of 10-100 mg of archaeological material can thus be characterized. Fourteen archaeological samples have been identified as birch bark pitches by comparison with recent pitches of known origin. In addition 28 substances present In recent barks and recent pitches could be Identified showing that the method developed can also be applied to the chemotaxonomy of broad-leaved trees.

Characterization of Waste Tar Associated with Abandoned Wood Chemical Plant Sites in Northwest Pennsylvania, USA

“…), it is unlikely that the types of wood used by the plants varied greatly since all chemical plants in the current study lay within forests of similar composition typical of the southern reaches of the hemlock-white pine-northern hardwood forests of eastern North America (Nichols 1935). The tree species from which wood tars and pitches were derived could be determined by analysis of patterns of their triterpenoid and steroid composition (Hayek et al 1990). However, wood chemical plants in the Allegheny High Plateau preferentially used maple and beech because of their greater yield of acetic acid and methanol (Taber 1975).…”

Studies in Organic Archaeometry VII ‐ Differentiation of Wood and Bark Pitches by Pyrolysis Capillary Gas Chromatography (PY‐CGC)

“…Concerning the instrumental equipment and the temperature profile during the manufacturing process pitch production was done as published previously 22,25 .…”

Analytical pyrolysis with in situ thermally assisted derivatisation, Py(HMDS)-GC/MS, for the chemical characterization of archaeological birch bark tar

“…Tar from Betulaceae bark has been found on arrowheads and flint tools from the prehistoric age and the tar has been interpreted as a residue of the original adhesives [3][4][5][6][7][8][9][10][11]. A chemical study of amorphous materials recovered from flint artefacts found in Campitello (Arezzo, Italy) revealed that birch bark tar was already being produced in the early-Palaeolithic period, and this represents the oldest finding of birch bark tar known until now [9,12].…”