Limitations in interpreting TMAH thermochemolysis of natural organic matter via consideration of glycine and alanine derivatives

Gallois, Nicolas; Templier, Joëlle; Derenne, Sylvie

doi:10.1016/j.orggeochem.2010.05.018

Cited by 6 publications

(5 citation statements)

References 17 publications

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“…The most abundant features in the chromatogram of the clear coating were N,N-Dimethylglycine methyl ester, followed by an unknown compound eluting at 5.5 min (Figure 10B). This unknown compound has a base peak at m/z 72 and an apparent mass of 131 amu, which is similar to the reported fragmentation pattern for N-N-dimethylalanine methyl ester [32]. As neither pyrrole nor indole are identified here, it is likely that these compounds are instead related to TMAH itself.…”

Section: Surface Coatingsupporting

confidence: 82%

Seventeenth-Century Barniz de Pasto Objects from the Collection of the Hispanic Society Museum & Library: Materiality and Technology

Basso,

McGeachy,

Mieites Alonso

et al. 2024

Heritage

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The Hispanic Society Museum & Library (HSML) holds a collection of nine viceregal barniz de Pasto objects, made by Indigenous artisans in the 17th and 18th centuries. Designed to imitate Asian lacquers and intended for European aesthetic tastes, barniz de Pasto is an example of Indigenous technique and knowledge that has survived to the present day. An in-depth analysis of five of these barniz de Pasto objects, dated to the first half and last quarter of the 17th century based on their iconography, was carried out through a combination of non-invasive and micro-invasive techniques, including portable X-ray fluorescence (pXRF) spectroscopy to investigate the possible presence of inorganic pigments, and fiber-optics reflectance spectroscopy (FORS) and reflectance imaging spectroscopy (RIS) to provide molecular information on colorants and their distributions across the objects. Dyes and pigments were also identified using Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and liquid chromatography/mass spectrometry (LC/MS). The nature of the resin was determined by FTIR and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), while the decoration stratigraphy and composition were analyzed by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). This paper confirms the use of mopa mopa, the resin used in the barniz de Pasto technique, in two objects not previously analyzed, and identifies indigo, insect-based red, calomel, lead white, and an unknown flavonol-based yellow dye, and challenges the use of calomel as a temporal marker for these works. Taken together, these results expand our understanding of the material use and explorations undertaken by artists during this time period to create such elaborate and enduring objects.

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Section: Surface Coatingsupporting

confidence: 82%

Seventeenth-Century Barniz de Pasto Objects from the Collection of the Hispanic Society Museum & Library: Materiality and Technology

Basso,

McGeachy,

Mieites Alonso

et al. 2024

Heritage

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“…MTBSTFA is a silyl reagent (Figure 1), which replaces any labile (reactive) hydrogen in chemical bonds (e.g., -OH, -NH 2 , -SH, and -COOH) with the nonpolar moiety -Si (CH 3 ) 2 C(CH 3 ) 3 (Kataoka, 1996). Thermochemolysis thermally degrades molecules before the substitution of acidic hydrogen by apolar groups from TMAH (i.e., methyl groups -CH 3 ; Challinor, 2001;Gallois et al, 2010;Shadkami & Helleur, 2010). After sample preparation, the stream of helium is divided: a 1:800 fraction is sent directly to the quadrupole mass spectrometer, while the sample is heated at a rate of 35°C/min (evolved gas analysis modes).…”

Section: The Quest For Organics On Marsmentioning

confidence: 99%

“…MTBSTFA is a silyl reagent (Figure ), which replaces any labile (reactive) hydrogen in chemical bonds (e.g., ‐OH, ‐NH 2 , ‐SH, and ‐COOH) with the nonpolar moiety ‐Si (CH 3 ) 2 C(CH 3 ) 3 (Kataoka, ). Thermochemolysis thermally degrades molecules before the substitution of acidic hydrogen by apolar groups from TMAH (i.e., methyl groups –CH 3 ; Challinor, ; Gallois et al, ; Shadkami & Helleur, ).…”

Section: Introductionmentioning

confidence: 99%

Role of the Tenax® Adsorbent in the Interpretation of the EGA and GC‐MS Analyses Performed With the Sample Analysis at Mars in Gale Crater

et al. 2019

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The Sample Analysis at Mars (SAM) experiment on the National Aeronautics and Space Administration Curiosity rover seeks evidence of organic compounds on the surface of Mars. Since the beginning of the mission, various organic molecules have been detected and identified. While several have been demonstrated to be indigenous to the Martian soil and rocks analyzed, others appear to have been produced from sources internal to the experiment. The objective of this study is to build an exhaustive molecular database to support the interpretation of SAM results by identifying all the chemical species produced from Tenax® adsorbents, by determining (1) the thermal degradation by-products of Tenax®, (2) the effect of Tenax® conditioning on the formation of Tenax® by-products, (3) the impact of MTBSTFA or a mixture of MTBSTFA and DMF on Tenax® decomposition, and (4) the reaction between Tenax® and calcium perchlorate. Our results indicate that the by-products of the SAM trap are due to the impact of trap heating, the impact of the derivatization reagent (MTBSTFA) and the presence of perchlorate in Martian soil. Some of these by-products are observed in the SAM gas chromatograph mass spectrometer data from Mars.

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“…Nitrogen-containing pyrolysate compounds are derived from proteins, nucleic acids and amino acids via decarboxylation, homolysis, cyclization and fragmentation. 20,22,26 Peaks of Nos. 40, 41, 43 and 45, which are common in plants, animals and fungi, 27 were detected in all HAs in this study.…”

Section: Detail Structural Character Of Hasmentioning

confidence: 99%

“…4), which is regarded as a pyrolysate product of polyphenol or proteins. 26,29,30 The conspicuous peaks of 3,4-dimethoxy-benzoic acid (No. 32) and 3,4,5-trimethoxybenzoic acid methyl esters (No.…”

Section: Detail Structural Character Of Hasmentioning

confidence: 99%

Influence of Land Use on the Structural Feature of Sedimentary Humic Acids in Rivers in Northwest Hokkaido, Japan

Iwai

Yamamoto

2019

ANAL. SCI.

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Colloidal organic matter is an important factor in our understanding of the transport of trace metals by rivers to coastal areas and the characteristics of organic matter in the sediment, including the effect of humic substances on the transport of such metals. The structural features of humic acids (HAs) derived from surface sediments collected from the mouths of four rivers in northwest Hokkaido, Japan, were evaluated from the perspective of land use in their basins. The sediments in two rivers (referred to as NS and SK) were lacking in HAs, but the sediments of the others (referred to as SM and PO) contained relatively high levels of HAs. UV-vis spectroscopic characteristics suggested that the HAs in SM and PO contained components derived from humified materials. The PO and SM basins contain rice paddy fields, and TMAH-py-GC/MS analysis showed that the pyrograms of paddy soil HA had a similar character to those of PO-HA and SM-HA samples. Thus, the differences of the structural features can be attributed to the land use in river basins. The findings indicate that the properties of organic river sediments are heavily influenced by the type of land use in the river basins.

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Limitations in interpreting TMAH thermochemolysis of natural organic matter via consideration of glycine and alanine derivatives

Cited by 6 publications

References 17 publications

Seventeenth-Century Barniz de Pasto Objects from the Collection of the Hispanic Society Museum & Library: Materiality and Technology

Seventeenth-Century Barniz de Pasto Objects from the Collection of the Hispanic Society Museum & Library: Materiality and Technology

Role of the Tenax® Adsorbent in the Interpretation of the EGA and GC‐MS Analyses Performed With the Sample Analysis at Mars in Gale Crater

Influence of Land Use on the Structural Feature of Sedimentary Humic Acids in Rivers in Northwest Hokkaido, Japan

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