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ABSTRACT: Amber samples from archaeological objects belonging to the collection of the Museo Civico Archeologico of Bologna were analysed by pyrolysis/gas chromatography/(ion-trap) mass spectrometry (PY/GC/MS) and Fourier-transform infrared spectroscopy (FTIR) to assess the geographic origin of the fossil resin. Both techniques showed potential in the study of amber, because they require small sample amounts, virtually no sample preparation and provide a fingerprint which is highly diagnostic of the material under investigation. Typical pyrograms, mass spectra and FTIR spectra are shown and compared to those obtained from standard amber of known geographical origin. The usefulness of composite mass spectra, namely mass spectra obtained by summing all or part of the mass spectra acquired within the pyrogram, to create a library of PY/GC/MS data and to compare samples is evaluated.
Rapid Communications in Mass Spectrometry 04/2005; 7(7):646 - 650. · 2.79 Impact Factor
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ABSTRACT: Some fractions of beer-factory wastewaters represent an important environmental concern owing to their high content of polyphenols and dark-brown color. The capacity of Coriolopsis gallica to preferentially degrade lignin has been successfully applied in our laboratory to the biotreatment and decolorization of paper-industry effluents. In this work, the ability of this white-rot fungus to degrade high-tannin-containing wastewaters is evaluated. Under all the conditions studied, effluent decolorization and chemical oxygen demand reduction achieved by C. gallica at day 12 of incubation were close to 50 and 65%, respectively. No adhesion of dark color to the fungal mycelium was observed suggesting that decolorization could be ascribed to C. gallica degradation systems. Mycelium dry-weight values showed that C. gallica is tolerant to relatively high tannin content present in the effluent samples. In the sample containing the highest effluent concentration (60% v/v), dry-weight values suggested an inhibition of fungal growth at day 6 of incubation and a further adaptation of the fungus to the stressing tannin effect at day 12 of fungal treatment. Pyrolysis/gas chromatography/mass spectrometry results showed a decrease of polyphenols pyrolysis products, mainly phenol and guaiacol, with the incubation time. All these results indicate the potential use of C. gallica in bioremediation of tannin-containing industrial wastewaters and in other applications where a reduction in polyphenols content is required. Copyright © 2000 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry 05/2000; 14(10):905 - 910. · 2.79 Impact Factor
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ABSTRACT: The pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS) results after fungal treatment of paper-industry effluents suggested a decrease of the relative amounts of lignin pyrolysis products and of the syringyl/guaiacyl ratio, in addition to some oxidation rate of the C3-alkyl chain in lignin units. The results obtained pointed to the potential of PY/GC/MS for monitoring the extent of fungal modification of lignins by biological systems based on the use of Trametes versicolor.
Rapid Communications in Mass Spectrometry 06/1993; 7(7):659 - 661. · 2.79 Impact Factor
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ABSTRACT: Different wheat straw fractions representative of industrial and laboratory-scale alkaline pulping processes have been studied by pyrolysis—gas chromatography/mass spectrometry (Py-GC/MS). For comparative purposes, a milled straw lignin from wheat straw was also studied.The pyrolytic patterns were suitable for estimating the extent to which lignin-derived material is present in the hemicellulose preparations, or hemicellulose-derived products contributed to the alkalilignin fractions. The results reflect the different efficiency of the treatments to remove lignin and carbohydrate during alkaline pulping of Gramineae straws. The virtual lack of carbohydrate-derived pyrolysis products was observed only in the alkalilignin preparation obtained with the highest NaOH concentration studied (1 M) at 30°C for 12 h.The pyrolysis data showed that the guaiacyl fragments were dominant in the lignin associated to hemicellulose fractions, suggesting structural relationships between hemicellulose and lignin through guaiacyl type units. This was complementary to the large amounts of syringyl units that remained in the alkalilignin preparations.Although Py-GC/MS provides markers for the major classes of cell wall components, such as lignin and structural polysaccharides, it does not yield fragments which could be ascribed with certainty to cinnamic acids, which are abundant and play an important role in cereal straws as lignin—carbohydrate linkages.
Journal of Analytical and Applied Pyrolysis.
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ABSTRACT: Nineteen α-amino acids were pyrolysed at 600°C using an integrated pyrolysis-gas chromatography/mass spectrometry system. Pyrograms, tabulated mass spectra and proposed identifications of the main pyrolysis fragments are reported. Diagnostic pyrolysis fragments were recognised for most of the α-amino acids (with the exception of histidine, glycine, serine, alanine and threonine) and their formation is rationalised by proposing four thermal degradation pathways.
Journal of Analytical and Applied Pyrolysis.
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ABSTRACT: Pyrolysis—gas chromatography mass spectrometry is shown to be a rapid technique, requiring no sample work-up, for the recognition of organic materials, namely animal glue, egg yolk and glair, and linseed oil and casein, commonly used as binding media in ancient paintings. Major compounds originating from the thermal decomposition of proteins are identified by their mass spectra and have been diagnostic for glue, glair and casein. C-16, C-18 and other lower molecular weight free fatty acids are significant markers for yolk and linseed oil; however, they are not detectable in their free form when present in low quantities or as salts. In this case, the use of simultaneous pyrolysis—methylation (SPM), by addition of an aqueous solution of tetramethylammonium hydroxide to the sample, is recommended. Chromatograms of pyrolysates of binding media and of samples from original paintings are shown.
Journal of Analytical and Applied Pyrolysis.
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ABSTRACT: Two native Chilean woods (Eucryphia cordifolia Cav. and Laurelia philippiana Looser) and their corresponding sound and degraded milled wood lignin preparations, were characterized by pyrolysis-gas chromatography/mass spectrometry. The main goal of this work was to study the chemical changes in a lignin molecule during the natural fungal decay. A higher proportion of syringyl (S) than guaiacyl (G) units was detected in the native wood of E. cordifolia ( ratio of 3.9), whereas L. philippiana native wood showed similar amounts of S and G units ( ratio of 0.9). The modified Björkman method used here proved to be a suitable procedure for removing almost all the carbohydrate fraction of wood, with only minor modifications (demethylations) to the resulting purified lignin. The alterations affecting the propane chain of lignin units (C3-alkyl chain oxidations and shortenings) observed in L. philippiana after Phlebia chrysocrea (Berk. and Curt.) decay were similar to these described in E. cordifolia by Ganoderma australe (Fr.), except that the former were only detected in S-lignin units. Additionally, in L. philippiana some demethylation reactions were also suggested, although oxidations were not observed in the Cβ-position. Both fungi produced a decrease in lignin content, independent of the different ratio of the studied woods. After the brown-rot fungus attack the lignin content did not change. Although this brown-rot microorganism does not substantially degrade lignin, it is able to produce some minor chemical alterations: demethylations and oxidations of lignin side-chains.
Journal of Analytical and Applied Pyrolysis.
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ABSTRACT: The black solid content of a red ceramic bottle (Cyprus, XIV-XIIIth Century B.C.) and the organic patinas on the bronze statue of Neptune (Bologna, 1566 A.D.) were analyzed by pyrolysis-gas chromatography/mass spectrometry (PY-GC/MS) and by GC/MS after extractions with organic solvents, using a capillary gas chromatograph coupled to an Ion Trap Mass Spectrometer. Results show that the supposedly bituminous material of the ceramic bottle is, in fact, a mixture of aliphatic mono- and di-carboxylic acids, palmitic acid being the main peak, probably deriving from a vegetable oil. The patinas on the Neptune statue result in pyrograms containing mainly palmitic acid and minor quantities of other aliphatic acids, which can be attributed to both protective coatings and atmospheric depositions. Pyrolysis works as a thermal desorption injector and is useful for the rapid analysis of small samples.
Journal of Analytical and Applied Pyrolysis 20:253-261. · 2.49 Impact Factor
