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Frank P.,Stanford University | Frank P.,SLAC | Caruso F.,University of Palermo | Caruso F.,Koninklijk Instituut voor Het Kunstpatrimonium Institute Royal du Patrimoine Artistique KIK IRPA | And 2 more authors.
Analytical Chemistry | Year: 2012

In 2008 the rostrum from an ancient warship was recovered from the Mediterranean near Acqualadrone, Sicily. To establish its provenance and condition, samples of black and brown rostrum wood were examined using sulfur K-edge X-ray absorption spectroscopy (XAS) and gas chromatography/mass spectrometry (GC/MS). GC/MS of pyrolytic volatiles yielded only guaiacyl derivatives, indicating construction from pinewood. A derivatized extract of black wood yielded forms of abietic acid and sandaracopimaric acid consistent with pine pitch waterproofing. Numerical fits to the sulfur K-edge XAS spectra showed that about 65% of the endogenous sulfur consisted of thiols and disulfides. Elemental sulfur was about 2% and 7% in black and brown wood, respectively, while pyritic sulfur was about 12% and 6%. About 2% of the sulfur in both wood types was modeled as trimethylsulfonium, possibly reflecting biogenic (dimethylsulfonio)propionate. High-valent sulfur was exclusively represented by sulfate esters, consistent with bacterial sulfotransferase activity. Traces of chloride were detected, but no free sulfate ion. In summary, the rostrum was manufactured of pine wood and subsequently waterproofed with pine pitch. The subsequent 2300 years included battle, foundering, and marine burial followed by anoxia, bacterial colonization, sulfate reduction, and mobilization of transition metals, which produced pyrite and copious appended sulfur functionality. © 2012 American Chemical Society.

Caruso F.,ETH Zurich | Caruso F.,University of Palermo | Caruso F.,Koninklijk Instituut voor Het Kunstpatrimonium Institute Royal du Patrimoine Artistique KIK IRPA | Chillura Martino D.F.,University of Palermo | And 6 more authors.
Microchemical Journal | Year: 2014

A multi-analytical investigation was carried out to study varnish micro-samples from historical stringed musical instruments from the collection of the "Vincenzo Bellini" Conservatory in Palermo (Italy).This paper reports on the results of the application of five micro-destructive techniques: optical microscopy analysis of cross-sections, micro-Fourier transform infrared spectroscopy, gas chromatography coupled with mass spectrometry, pyrolysis gas chromatography coupled with mass spectrometry with thermochemolysis, and environmental scanning electron microscopy with X-ray microanalysis.The study provides microchemical information about the composition of the varnishes of the instruments of this collection. The results show that the varnish on all the sampled instruments has a consistent formulation - mainly constituted by a mixture of a tree diterpenoid resin, shellac, and a drying oil. The identification of other organic and inorganic materials is also discussed. It is concluded that the luthiers manufacturing such beautiful instruments did not use any exotic ingredients in the formulations that could be attributed to a secret recipe. © 2014 Elsevier B.V.

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