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Updated: Aug 16, 2026

Quantitative 31P NMR Analysis of Lignins and Tannins
Published on: August 2, 2021
Characterization of polyphenols from plant materials through their silylation and 29Si NMR spectroscopy-line
Jan Schraml1, Vratislav Blechta, Jan Sýkora
1Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Rozvojová 135, 16502, Prague 6, Czech Republic. schraml@icpf.cas.cz
Abstract:
The lines in (29)Si NMR spectra of silylated polyphenols and some other compounds are difficult to assign owing to the absence of couplings with protons outside the silyl group. The assignment can be derived through small (n)J((29)Si, (13)C) couplings (n > 1). Using a previously described method for measurements of these couplings, the assignment procedure is demonstrated here on three examples of trimethylsilylated phenols: 7-hydroxyflavone, ferulic acid, and quercetin. In some cases the procedure can be used to identify carbon atoms to which the siloxy groups are attached.
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