Site-specific carbon isotope ratio measurements by quantitative C NMR (C-qNMR), Orbitrap-MS, and GC-IRMS offer a new dimension to conventional bulk carbon isotope ratio measurements used in food provenance, forensics, and a number of other applications. While the site-specific measurements of carbon isotope ratios in vanillin by C-qNMR or Orbitrap-MS are powerful new tools in food analysis, there are a limited number of studies regarding the validity of these measurement results. Here we present carbon site-specific measurements of vanillin by GC-IRMS and C-qNMR for methoxy carbon. Carbon isotope delta (δC) values obtained by these different measurement approaches demonstrate remarkable agreement; in five vanillin samples whose bulk δC values ranged from -31‰ to -26‰, their δC values of the methoxy carbon ranged from -62.4‰ to -30.6‰, yet the difference between the results of the two analytical approaches was within ±0.6‰. While the GC-IRMS approach afforded up to 9-fold lower uncertainties and required 100-fold less sample compared to the C-qNMR, the C-qNMR is able to assign δC values to all carbon atoms in the molecule, not just the cleavable methoxy group.
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http://dx.doi.org/10.1021/jasms.3c00327 | DOI Listing |
Physiol Plant
January 2025
Department of Radioecology, Institute for Environmental Sciences, Aomori, Japan.
The use of stored carbon is essential for new organ development in deciduous trees during early spring. However, the contribution of carbon to the development of new organs in early spring of subsequent years is not well understood. Using a C labelling approach, we investigated the reallocation of assimilated carbon into new aboveground organs on apple (Malus domestica) saplings in the following two years.
View Article and Find Full Text PDFSci Rep
January 2025
Institute of Environmental Physics, Heidelberg University, Im Neuenheimer Feld 229, 69120, Heidelberg, Germany.
The deep Southern Ocean (SO) circulation plays a key role in the storage and release of CO in Earth's climate system. The uptake and release of CO strongly depend on the redistribution of well and poorly ventilated deep ocean water masses. Recently, evidence was found for possible stronger Pacific deep water overturning and subsequent intrusion into the SO during periods of reduced AMOC.
View Article and Find Full Text PDFSci Data
January 2025
Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
Permafrost soils store vast amounts of organic carbon, and their thawing due to climate warming accelerates the release of carbon as methane and carbon dioxide, exacerbating global climate change. Understanding the distribution of greenhouse gases trapped in these soils and predicting their behavior upon thawing is essential for accurately modeling climate feedbacks. This study presents an integrated biogeochemical and microbial dataset from ~1.
View Article and Find Full Text PDFAnal Methods
January 2025
National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing, Beijing, 100029, China.
With the increasing demand for energy, nuclear energy has been developing rapidly. The quantitative detection and qualitative identification of uranium (U) are of great significance for the comprehensive and efficient use of U resources and the control of nuclear and radioactive substances. In this study, the detection of U is divided into liquid sample detection, solid sample detection, gas sample detection, and industrial detection from the perspectives of the sample state and detection environment.
View Article and Find Full Text PDFEnviron Res
January 2025
State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, National Hulunbuir Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address:
Increasing extreme precipitation and drought events along changes in their seasonal patterns due to climate change are expected to have profound consequences for carbon cycling. However, how these climate extremes impact ecosystem respiration (R) and whether these impacts differ between seasons remain unclear. Here, we reveal the responses of R and its components to extreme precipitation and drought in spring and summer by conducting a five-year manipulative experiment in a temperate meadow steppe.
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