Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis
This study examines a boreal peatland (the Sagnes peatland, Fanay, Limousin, France) with a depth of 1 m. This peatland is currently in the late stages of organic deposition, as evidenced by the growth of <i>Carex</i> species, along with <i>Sphagnum</i> mosses, in the uppermo...
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2024-11-01
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| author | Sara Moghnie Emil Obeid Jalal Halwani Laurent Grasset Khaled Younes |
| author_facet | Sara Moghnie Emil Obeid Jalal Halwani Laurent Grasset Khaled Younes |
| author_sort | Sara Moghnie |
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| description | This study examines a boreal peatland (the Sagnes peatland, Fanay, Limousin, France) with a depth of 1 m. This peatland is currently in the late stages of organic deposition, as evidenced by the growth of <i>Carex</i> species, along with <i>Sphagnum</i> mosses, in the uppermost level. To gain molecular insights, we conducted an analysis of the lignin and polyphenolic counterparts using HMDS (hexamethyldisilazane) thermochemolysis, enabling the identification of lignin degradation proxies. The goal was to develop characteristic indicators for the state of lignin degradation based on the relative distribution of lignin phenols, measured by gas chromatography coupled with mass spectrometry (GC-MS) after the HMDS thermochemolysis. For that purpose, the singular contribution of the 11 aromatic moieties yielded, along with SGC (sum of lignin moieties) and the most lignin degradation proxies, were applied. It has been shown that HMDS thermochemolysis exhibited the capacity to reveal oxidized and degraded lignin fractions, following the increasing trend yielded for most moieties and SGC proxy, in the mesotelm and catotelm layers. In addition, the C/G (Cinnamyl/Guaiacyl) and S/G (Syringyl/Guaiacyl) ratios showed their highest input in the upper half of the core. This bias in the aforementioned ratios could indicate that HMDS thermochemolysis is to be applied for geological samples, where low G-compounds exist. For the sake of validating HMDS thermochemolysis’ application, Principal Component Analysis (PCA) was then applied to the molecular fingerprint. For ratios and proxies of aromatic moieties of HMDS thermochemolysis, the PCA approach exhibited a higher contribution (79%). This indicates the efficiency of these ratios in describing the molecular fingerprint of peat depth records. In addition, a higher separation between the contributions of the investigated variables (molecular proxies) along the first two PCs was noticed. In other words, the variables that showed a high contribution towards PC<sub>1</sub> exhibited a low contribution towards PC<sub>2</sub>, and vice versa. These findings indicate the high reliance of applying the ratios and proxies of HMDS thermochemolysis. |
| format | Article |
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| institution | OA Journals |
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| language | English |
| publishDate | 2024-11-01 |
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| spelling | doaj-art-a301415315a64fbcbd63397b9714722d2025-08-20T01:55:41ZengMDPI AGMolecules1420-30492024-11-012923553710.3390/molecules29235537Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component AnalysisSara Moghnie0Emil Obeid1Jalal Halwani2Laurent Grasset3Khaled Younes4College of Engineering and Technology, American University of the Middle East, Egaila 54200, KuwaitCollege of Engineering and Technology, American University of the Middle East, Egaila 54200, KuwaitWater and Environment Sciences Laboratory, Lebanese University, Tripoli P.O. Box 6573/14, LebanonUniversité de Poitiers, Institut de Chimie des Milieux et Matériaux de Poitiers IC2MP, UMR CNRS 7285, Equipe Eaux, Biomarqueurs, Contaminants Organiques, Milieux, B27, 4 rue Michel Brunet, CEDEX 9, 86073 Poitiers, FranceCollege of Engineering and Technology, American University of the Middle East, Egaila 54200, KuwaitThis study examines a boreal peatland (the Sagnes peatland, Fanay, Limousin, France) with a depth of 1 m. This peatland is currently in the late stages of organic deposition, as evidenced by the growth of <i>Carex</i> species, along with <i>Sphagnum</i> mosses, in the uppermost level. To gain molecular insights, we conducted an analysis of the lignin and polyphenolic counterparts using HMDS (hexamethyldisilazane) thermochemolysis, enabling the identification of lignin degradation proxies. The goal was to develop characteristic indicators for the state of lignin degradation based on the relative distribution of lignin phenols, measured by gas chromatography coupled with mass spectrometry (GC-MS) after the HMDS thermochemolysis. For that purpose, the singular contribution of the 11 aromatic moieties yielded, along with SGC (sum of lignin moieties) and the most lignin degradation proxies, were applied. It has been shown that HMDS thermochemolysis exhibited the capacity to reveal oxidized and degraded lignin fractions, following the increasing trend yielded for most moieties and SGC proxy, in the mesotelm and catotelm layers. In addition, the C/G (Cinnamyl/Guaiacyl) and S/G (Syringyl/Guaiacyl) ratios showed their highest input in the upper half of the core. This bias in the aforementioned ratios could indicate that HMDS thermochemolysis is to be applied for geological samples, where low G-compounds exist. For the sake of validating HMDS thermochemolysis’ application, Principal Component Analysis (PCA) was then applied to the molecular fingerprint. For ratios and proxies of aromatic moieties of HMDS thermochemolysis, the PCA approach exhibited a higher contribution (79%). This indicates the efficiency of these ratios in describing the molecular fingerprint of peat depth records. In addition, a higher separation between the contributions of the investigated variables (molecular proxies) along the first two PCs was noticed. In other words, the variables that showed a high contribution towards PC<sub>1</sub> exhibited a low contribution towards PC<sub>2</sub>, and vice versa. These findings indicate the high reliance of applying the ratios and proxies of HMDS thermochemolysis.https://www.mdpi.com/1420-3049/29/23/5537thermochemolysishexamethyldisilazanePrincipal Component Analysispeatland |
| spellingShingle | Sara Moghnie Emil Obeid Jalal Halwani Laurent Grasset Khaled Younes Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis Molecules thermochemolysis hexamethyldisilazane Principal Component Analysis peatland |
| title | Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis |
| title_full | Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis |
| title_fullStr | Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis |
| title_full_unstemmed | Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis |
| title_short | Unlocking Molecular Fingerprint of an Ombrotrophic Peat Bog: Advanced Characterization Through Hexamethyldisilazane Thermochemolysis and Principal Component Analysis |
| title_sort | unlocking molecular fingerprint of an ombrotrophic peat bog advanced characterization through hexamethyldisilazane thermochemolysis and principal component analysis |
| topic | thermochemolysis hexamethyldisilazane Principal Component Analysis peatland |
| url | https://www.mdpi.com/1420-3049/29/23/5537 |
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