The scope of pyrolysis methylation reactions

Challinor, J.M.

doi:10.1016/0165-2370(91)80059-h

Cited by 146 publications

(44 citation statements)

References 4 publications

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“…However, a major drawback of conventional pyrolysis techniques is the occurrence of secondary reactions, such as the recombination of pyrolysis products, decarboxylation and dehydration (Challinor, 2001). The addition of TMAH enables the avoidance of these secondary reactions and generally provides a greater sensitivity than conventional pyrolysis (Challinor, 1991(Challinor, , 2001. THM also enables the analysis of polymeric or macromolecular substances that are resistant to hydrolysis.…”

Section: Advantages Of Thm Over Conventional Pyrolysismentioning

confidence: 99%

Decomposition of Juncus seeds in a valley mire (Faroe Islands) over a 900 year period

Yeloff

Blokker

Bartlett

et al. 2008

Organic Geochemistry

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The influence of past depositional environments on the chemistry of sub-fossil Juncus seed coats (testa) from the top 1 m (corresponding to ca. 900 years of peat accumulation) of a peat bog in the Faroe Islands was examined. The chemistry of the testa of fresh Juncus seeds were characterised using thermally assisted pyrolysis and methylation (THM) in the presence of tetramethyl ammonium hydroxide (TMAH) and 'type' compounds were identified, representative of the major chemical groups in the testa (cellulose-related sugars, lignin-related phenolics, fatty acids). The abundance of the 'type' compounds in the products from sub-fossil testae (the internal tissues of the seeds do not survive beyond the very early stages of decomposition) was then quantified at contiguous 1 cm depth intervals. Major losses of C 18 unsaturated fatty acid methyl esters and sugars were associated with the fresh to sub-fossil transition at ca. 7 cm depth. The preservation of the phenolic ferulic acid in the seed testa appears to be favoured by the input of small basaltic particles from the nearby stream channel. The mechanism by which inwash of inorganic material may be responsible for the improved chemical preservation of the Juncus seed testa is, however, unclear. The sugars were easily metabolised by microorganisms under aerobic conditions of low water table and preserved under anoxic conditions with high water table, suggesting that a drier mire surface may result in the more efficient depletion of polysaccharides and cellulose during the initial stage of decomposition in the acrotelm.

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Section: Advantages Of Thm Over Conventional Pyrolysismentioning

confidence: 99%

Decomposition of Juncus seeds in a valley mire (Faroe Islands) over a 900 year period

Yeloff

Blokker

Bartlett

et al. 2008

Organic Geochemistry

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“…Whereas for the former, good information could be gained by a variety of techniques (colorimetric assays, 2 infrared spectroscopy, 3 acid hydrolysis followed by chromatography 4,5 ), for the latter, the detection and identification of specific resins in paint media was not possible before the use of high-resolution gas chromatography, 6,7 Fourier-transform infrared spectroscopy and gas chromatography/mass spectrometry. 9 More recently, new techniques such as pyrolysis/gas chromatography, 10 pyrolysis/gas chromatography/mass spectrometry, 11,12 ion-source pyrolysis/mass spectrometry 13 and simultaneous pyrolysis-methylation/gas chromatography/mass spectrometry 14 have afforded unequivocal assignments to the resin composition of art materials, and have also improved the information obtainable from carbohydrate-based media, 15 revealing the possibility of obtaining characteristic fingerprints for the different materials.…”

Section: Gummentioning

confidence: 99%

Curie-point Pyrolysis/Gas Chromatography/Mass Spectrometry in the Art Field. Part 3: The Characterization of Some Non-proteinaceous Binders

Stevanato¹,

Rovea²,

Carbini³

et al. 1997

Rapid Commun. Mass Spectrom.

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Curie-point pyrolysis/gas chromatography/mass spectrometry has been employed to characterize nine non-proteinaceous media used in the past as binders in works of art. Obtaining their fingerprints (achieved by both chromatographic patterns and mass spectral data of the individual components) is important in the context of the building of a complete database to be used in an analytical approach to the field of museum materials and restoration.

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“…The pyrolysis of polar macromolecular materials is known to produce volatile polar products, only some of which can be chromatographed; polar products remain attached to the column, undetected and unquantified. Pyrolysis in the presence of TMAH derivatizes polar compounds to become less polar products, which are more amenable to chromatographic separation (Challinor, 1989;del R! ıo et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Preservation of peptide moieties in three Spanish sulfur-rich Tertiary kerogens

Rı́o

Olivella

Knicker

et al. 2004

Organic Geochemistry

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Thermochemolysis with tetramethylammonium hydroxide (TMAH) and solid-state 15 N NMR were utilized for the characterization of refractory organic nitrogen in Tertiary Spanish kerogens. The samples included sulfur-rich oil shales from the Ribesalbes (Serravallian), Libros (Tortonian) and Cerdanya (Tortonian) basins. Analysis using solid state 15 N NMR showed that part of the refractory nitrogen in the kerogens corresponds to amide groups. Moreover, the release of amino acid derivatives after pyrolysis in the presence of TMAH indicated that this amide-N arose from peptide moieties. The amino acids released from the kerogens were dominated by high amounts of glycine and alanine. Minor amounts of aspartic acid, serine, a-aminobutyric acid and other unidentified amino acids were also detected. Because proteinaceous structures, including small peptides, are generally considered as being highly sensitive to diagenetic degradation, encapsulation of labile peptide material into aliphatic structures in S-rich kerogens (probably via lipid sulfurization) has been proposed to explain the survival of these moieties. Substantial amounts of fatty acids (as methyl esters) were also released from all the kerogens after pyrolysis/TMAH, indicating their highly aliphatic character. The production of both fatty acids and amino acids from the kerogens supports the encapsulation process. !

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The scope of pyrolysis methylation reactions

Cited by 146 publications

References 4 publications

Decomposition of Juncus seeds in a valley mire (Faroe Islands) over a 900 year period

Decomposition of Juncus seeds in a valley mire (Faroe Islands) over a 900 year period

Curie-point Pyrolysis/Gas Chromatography/Mass Spectrometry in the Art Field. Part 3: The Characterization of Some Non-proteinaceous Binders

Preservation of peptide moieties in three Spanish sulfur-rich Tertiary kerogens

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