1. Probing the aluminum complexation by Siberian riverine organic matter using solid-state DNP-NMR.
- Author
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Pourpoint, Frédérique, Templier, Joëlle, Anquetil, Christelle, Vezin, Hervé, Trébosc, Julien, Trivelli, Xavier, Chabaux, François, Pokrovsky, Oleg S., Prokushkin, Anatoly S., Amoureux, Jean-Paul, Lafon, Olivier, and Derenne, Sylvie
- Subjects
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COMPLEXATION reactions , *ALUMINUM compounds , *ORGANIC compounds , *CHEMICAL species , *METAL ions , *ELECTRON paramagnetic resonance , *NUCLEAR magnetic resonance spectroscopy - Abstract
In a Siberian river, the concentrations of chemical species vary with the hydrological regime. Dissolved Organic Matter (DOM) and aluminum ions show a parallel trend in the course of the hydrological year. However, the speciation of aluminum in this natural environment remains an open question. We propose here a combination of spectroscopic techniques to investigate the proximity between the aluminum atoms and DOM. First, one-dimensional (1D) solid-state Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR) and 1D and 2D solution NMR spectra were acquired, providing a clear overview of the DOM composition. Second, the sensitivity enhancement yielded by Dynamic Nuclear Polarization enabled the NMR detection of proximities between the 27 Al and 13 C nuclei. Hence, we show that 8.3 ± 1.3% of the carboxylate groups observed by NMR are connected to the Al 3 + ions in the DOM sample. We here demonstrate for the first time how advanced solid-state NMR methods can provide key information about the localization of aluminum in such complex natural materials. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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