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001-es BibID:BIBFORM058627
Első szerző:Kéri Mónika (környezetkutató vegyész)
Cím:13C NMR analysis of cellulose samples from different preparation methods / Mónika Kéri, László Palcsu, Marianna Túri, Enikő Heim, Andrea Czébely, Levente Novák, István Bányai
Dátum:2015
ISSN:0969-0239
Megjegyzések:Alpha-cellulose is a part of the wooden material that preserves isotopic composition during tree-growth, and therefore provides important indirect data for paleoclimatological studies. For this reason, it is exceptionally important to extract the alpha-cellulose component from plants, e.g. from tree rings of wood. Since the cell wall of plant cells consists of multicomponent polysaccharides, the extraction of cellulose from wood is not an obvious task. In this paper, we describe, evaluate and compare nine methods, based on the literature and experimental observations, for obtaining cellulose from tree rings of wood. We show that the distortionless enhancement by polarization transfer (DEPT-135) variant of liquidstate 13C NMR spectroscopy is a powerful analytical method for monitoring the preparation process. Trifluoroacetic acid was applied as solvent for the NMR analysis. We proved that all the preparation methods give pure cellulose samples without hemicellulose and lignin content, and we propose methods resulting in non-fragmented cellulose. 13C and 18O isotope ratio measurements have shown that all the applied extraction methods result in similar isotope ratios, thus they are suitable for paleoclimatological studies.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
cellulóz
paleoklimatológia
13C NMR
izotóp összetétel
Megjelenés:Cellulose. - 22 : 4 (2015), p. 2211-2220. -
További szerzők:Palcsu László (1975-) (fizikus) Túri Marianna (1988-) (geográfus-geoinformatikus) Heim Enikő (1986-) (vegyész) Czébely Andrea (1983-) (biológus) Novák Levente (1967-) (biológus) Bányai István (1953-) (vegyész)
Pályázati támogatás:TÁMOP-4.2.2.A-11/1/KONV-2012-0043
TÁMOP
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001-es BibID:BIBFORM106949
Első szerző:Túri Marianna (geográfus-geoinformatikus)
Cím:ICER carbonate clumped isotope analysis of karst deposits / Marianna Túri, Andrea Czébely, Diána Kiss, Marjan Temovski, László Palcsu, László Rinyu
Dátum:2022
Megjegyzések:In April 2018, a 253 Plus 10 kV isotope ratio mass spectrometer equipped with a Kiel IV automatic carbonate device (Thermo Scientific) was installed at the Isotope Climatology and Environmental Research Centre (ICER), Institute for Nuclear Research, Debrecen, Hungary. Beside the analysis of the conventional carbon and oxygen isotope composition of small carbonate samples, the main application of our system is the clumped isotope thermometry of different kind of carbonate samples. The clumped carbonate measurements are carried out following the methodology of Bernasconi et al. [1]. Carbonate replicate samples (100-110 ?g) are digested by three drops of 1.95 g/cm3 phosphoric acid in the Kiel IV carbonate device. The evolved CO2 is passed through a micro-volume inlet system, which contains two LN2 traps and a Porapak trap in order to eliminate the possible hydrocarbon contaminants. The Easotope software is used for data evaluation of the measurements using the Brand parameters [2] and the carbon dioxide equilibrium scales [3, 4]. To demonstrate the achievable accuracy, precision and long-term stability of the measurement system at ICER, we analyzed international carbonate reference materials and proposed standards (ETH4, IAEA-C1, IAEA-C2, NBS-18, NBS-19, Merck Carbonate) and naturally formed travertine samples (known formation temperatures are in the range of 5-95?C) and compared them to formerly published data of two reputable laboratories from the clumped community [1, 5]. We also applied clumped carbonate analysis to several karst related research topics. One aspect is the suitability of tufa deposits as a paleoclimate archive, even if kinetic fractionation might play a significant role during carbonate formation. Another aspect is the application of clumped isotope thermometry to mammillary speleothems and hydrothermal carbonates as part of paleoclimate and speleogenetic studies. In the poster we will present our current achievements in the field of carbonate clumped isotope measurement, as well as some results on clumped isotope analysis of various carbonate deposits (tufa, mammillary speleothems, hydrothermal carbonates, dolomites) from different karst environments.
Tárgyszavak:Természettudományok Földtudományok előadáskivonat
könyvrészlet
Megjelenés:Climate Change : The Karst Record IX (KR9) Programme & abstract / eds. Gina Moseley, Mojgan Soleimani, Linda Partl, et al. - p. 164. -
További szerzők:Czébely Andrea (1983-) (biológus) Kiss Diána Temovski, Marjan Palcsu László (1975-) (fizikus) Rinyu László (fizikus)
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