{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T08:46:18Z","timestamp":1791017178917,"version":"4.1.0"},"reference-count":42,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2011,1,28]],"date-time":"2011-01-28T00:00:00Z","timestamp":1296172800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Solid state 13C-NMR spectra of pure tannin powders from four different sources \u2013 mimosa, quebracho, chestnut and tara \u2013 are readily distinguishable from each other, both in pure commercial powder form, and in leather which they have been used to tan.  Groups of signals indicative of the source, and type (condensed vs. hydrolyzable) of tannin used in the manufacture are well resolved in the spectra of the finished leathers.  These fingerprints are compared with those arising from leathers tanned with other common tanning agents.  Paramagnetic chromium (III) tanning causes widespread but selective disappearance of signals from the spectrum of leather collagen, including resonances from acidic aspartyl and glutamyl residues, likely bound to Cr (III) structures. Aluminium (III) and glutaraldehyde tanning both cause considerable leather collagen signal sharpening suggesting some increase in molecular structural ordering. The 27Al-NMR signal from the former material is consistent with an octahedral coordination by oxygen ligands. Solid state NMR thus provides easily recognisable reagent specific spectral fingerprints of the products of vegetable and some other common tanning processes. Because spectra are related to molecular properties, NMR is potentially a powerful tool in leather process enhancement and quality or provenance assurance.<\/jats:p>","DOI":"10.3390\/molecules16021240","type":"journal-article","created":{"date-parts":[[2011,1,31]],"date-time":"2011-01-31T11:44:06Z","timestamp":1296474246000},"page":"1240-1252","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":36,"title":["Tannin Fingerprinting in Vegetable Tanned Leather by Solid State NMR Spectroscopy and Comparison with Leathers Tanned by Other Processes"],"prefix":"10.3390","volume":"16","author":[{"given":"Frederik H.","family":"Romer","sequence":"first","affiliation":[{"name":"Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew P.","family":"Underwood","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nadine D.","family":"Senekal","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein 9301, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susan L.","family":"Bonnet","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein 9301, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melinda  J.","family":"Duer","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David G.","family":"Reid","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan H.","family":"Van der Westhuizen","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of the Free State, 205 Nelson Mandela Drive, Park West, Bloemfontein 9301, South Africa"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2011,1,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1039\/cs9972600111","article-title":"Modern tanning chemistry","volume":"1997","author":"Covington","year":"1997","journal-title":"Chem. Soc. Rev."},{"key":"ref_2","unstructured":"Covington, A.D. (2009). Tanning Chemistry: The Science of Leather, RSC Publishing."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"424","DOI":"10.1007\/s00216-003-1804-6","article-title":"The application of NMR and MS methods for detection of adulteration of wine, fruit juices, and olive oil. A review","volume":"376","author":"Ogrinc","year":"2003","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1021\/bk-2004-0864.ch017","article-title":"Interaction between cellulose I and hemicelluloses studied by spectral fitting of CP\/MAS C-13-NMR spectra","volume":"864","author":"Larsson","year":"2004","journal-title":"Hemicelluloses: Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/S0169-409X(01)00101-6","article-title":"Characterization of the solid-state: spectroscopic techniques","volume":"48","author":"Bugay","year":"2001","journal-title":"Advan. Drug Delivery Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1016\/0146-6380(88)90145-3","article-title":"Detection of Tannins in Modern and Fossil Barks and in Plant Residues by High-Resolution Solid-State C-13 Nuclear Magnetic-Resonance","volume":"12","author":"Wilson","year":"1988","journal-title":"Org. Geochem."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3600","DOI":"10.1128\/aem.62.10.3600-3604.1996","article-title":"Biological degradation of tannins in sericea lespedeza (Lespedeza cuneta) by the white rot fungi Ceriporiopsis subvermispora and Cyathus stercoreus analyzed by solid-state C-13 nuclear magnetic resonance spectroscopy","volume":"62","author":"Gamble","year":"1996","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_8","first-page":"431","article-title":"Characterization of high-tannin fractions from humus by carbon-13 cross-polarization and magic-angle spinning nuclear magnetic resonance","volume":"31","author":"Lorenz","year":"2002","journal-title":"J. Environ. Qual."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"779","DOI":"10.1016\/S0038-0717(99)00201-1","article-title":"Litter decomposition and humus characteristics in Canadian and German spruce ecosystems: information from tannin analysis and C-13 CPMAS NMR","volume":"32","author":"Lorenz","year":"2000","journal-title":"Soil Biol. Biochem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1268","DOI":"10.1016\/j.eurpolymj.2010.03.002","article-title":"Characterization of Acacia mangium polyflavonoid tannins by MALDI-TOF mass spectrometry and CP-MAS 13C NMR","volume":"46","author":"Hoong","year":"2010","journal-title":"Eur. Polym. J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.indcrop.2010.03.010","article-title":"MALDI-TOF and 13C NMR characterization of maritime pine industrial tannin extract","volume":"32","author":"Navarrete","year":"2010","journal-title":"Ind. Crops Prod."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2119","DOI":"10.1023\/A:1005568416040","article-title":"Evaluation of methods for measuring polyphenols in conifer foliage","volume":"26","author":"Yu","year":"2000","journal-title":"J. Chem. Ecol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1046\/j.1365-2389.2001.00364.x","article-title":"Solid-state C-13-NMR dipolar dephasing experiments for quantifying protonated and non-protonated carbon in soil organic matter and model systems","volume":"52","author":"Smernik","year":"2001","journal-title":"Eur. J. Soil Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1016\/j.indcrop.2009.03.005","article-title":"Cornstarch and tannin in phenol-formaldehyde resins for plywood production","volume":"30","author":"Moubarik","year":"2009","journal-title":"Ind. Crops Prod."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1007\/s00107-009-0357-6","article-title":"Development and optimization of a new formaldehyde-free cornstarch and tannin wood adhesive","volume":"68","author":"Moubarik","year":"2010","journal-title":"Eur. J. Wood Wood Prod."},{"key":"ref_16","first-page":"31","article-title":"Structural beams from thick wood panels bonded industrially with formaldehyde-free tannin adhesives","volume":"56","author":"Pichelin","year":"2006","journal-title":"Forest Prod. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1081\/WCT-120021924","article-title":"NMR estimation of extractables from bark: Analysis method for quantifying tannin extraction from bark","volume":"23","author":"Grigsby","year":"2003","journal-title":"J. Wood Chem. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1023\/A:1023346814391","article-title":"Dynamic mechanical analysis (DMA), C-13 solid state NMR and micro-thermomechanical studies of historical parchment","volume":"71","author":"Odlyha","year":"2003","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_19","first-page":"83","article-title":"Lightfast and high shrinkage temperature leather produced using vegetable tannins and novel melamine-urea-formaldehyde tanning formulations","volume":"98","author":"Simon","year":"2003","journal-title":"J. Amer. Leather Chem. Assoc."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1505","DOI":"10.1021\/ac802052a","article-title":"Nuclear magnetic resonance and electron paramagnetic resonance as analytical tools to investigate structural features of archaeological leathers","volume":"81","author":"Bardet","year":"2009","journal-title":"Anal. Chem."},{"key":"ref_21","first-page":"225","article-title":"A conformational study of collagen as affected by tanning procedures","volume":"92","author":"Brown","year":"1997","journal-title":"J. Amer. Leather Chem. Assoc."},{"key":"ref_22","first-page":"401","article-title":"Approach to a tanning mechanism: Study of the interaction of aluminum sulfate with collagen","volume":"100","author":"Brown","year":"2005","journal-title":"J. Amer. Leather Chem. Assoc."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1696","DOI":"10.1890\/0012-9658(1997)078[1696:DOSAAA]2.0.CO;2","article-title":"Diversity of structure and antiherbivore activity in condensed tannins","volume":"78","author":"Ayres","year":"1997","journal-title":"Ecology"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Czochanska, Z., Foo, L.Y., Newman, R.H., and Porter, L.J. (1980). Polymeric Proanthocyanidins - Stereochemistry, Structural Units, and Molecular-Weight. J. Chem. Soc.-Perkin Trans. 1, 2278\u20132286.","DOI":"10.1039\/p19800002278"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"868","DOI":"10.1002\/mrc.1867","article-title":"A 3D structural and conformational study of procyanidin dimers in water and hydro-alcoholic media as viewed by NMR and molecular modeling","volume":"44","author":"Tarascou","year":"2006","journal-title":"Magn. Resonance Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"887","DOI":"10.1002\/(SICI)1097-458X(199611)34:11<887::AID-OMR995>3.0.CO;2-U","article-title":"H-1 and C-13 NMR assignments of some green tea polyphenols","volume":"34","author":"Davis","year":"1996","journal-title":"Magn. Resonance Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"7531","DOI":"10.1016\/S0032-3861(01)00216-6","article-title":"MALDI-TOF mass spectrometry of polyflavonoid tannins","volume":"42","author":"Pasch","year":"2001","journal-title":"Polymer"},{"key":"ref_28","first-page":"325","article-title":"Collagen and polyphenols: New relationships and new outcomes. Part 1. Flavonoid reactions for new tanning processes","volume":"100","author":"Covington","year":"2005","journal-title":"J. Amer. Leather Chem. Assoc."},{"key":"ref_29","unstructured":"Covington, A.D. (2009). Tanning Chemistry: the Science of Leather, RSC Publishing."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1515\/hfsg.1997.51.3.235","article-title":"Analytical studies on tara tannins","volume":"51","author":"Galvez","year":"1997","journal-title":"Holzforschung"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3847","DOI":"10.1002\/app.30377","article-title":"Polymer Structure of Commercial Hydrolyzable Tannins by Matrix-Assisted Laser Desorption\/Ionization-Time-of-Flight Mass Spectrometry","volume":"113","author":"Pizzi","year":"2009","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/S0377-8401(01)00227-9","article-title":"Analysis of hydrolysable tannins","volume":"91","year":"2001","journal-title":"Anim. Feed Sci. Technol."},{"key":"ref_33","first-page":"179","article-title":"Synthesis and spectroscopic characterisation of the polygalloyl esters of polyols-models for gallotannins","volume":"87","author":"Tang","year":"2003","journal-title":"J. Soc. Leather Technol. Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1021\/np900829g","article-title":"Hydrolyzable Tannins of Tamaricaceous Plants. III. Hellinoyl- and Macrocyclic-Type Ellagitannins from Tamarix nilotica","volume":"73","author":"Orabi","year":"2010","journal-title":"J. Nat. Prod."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"914","DOI":"10.1021\/np800015p","article-title":"Phenolic glycosides from the stem bark of Caryocar villosum and C-glabrum","volume":"71","author":"Magid","year":"2008","journal-title":"J. Nat. Prod."},{"key":"ref_36","unstructured":"Duer, M.J. (2004). Introduction to Solid-state NMR Spectroscopy, Blackwell Science."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1002\/bip.20217","article-title":"Solid-state NMR studies of collagen-based parchments and gelatin","volume":"77","author":"Aliev","year":"2005","journal-title":"Biopolymers"},{"key":"ref_38","unstructured":"Dwek, R.A. (1973). NMR in Biochemistry, Clarendon."},{"key":"ref_39","first-page":"1","article-title":"Mechanistic Studies of Mineral Tanning .1. Solid-State Al-27 Nmr-Studies and the Thermodynamics of Shrinking","volume":"73","author":"Covington","year":"1989","journal-title":"J. Soc. Leather Technol. Chem."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1016\/S1090-7807(03)00253-2","article-title":"Preparation of protein nanocrystals and their characterization by solid state NMR","volume":"165","author":"Martin","year":"2003","journal-title":"J. Magn. Resonance"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3467","DOI":"10.1021\/j100844a056","article-title":"Aluminum complexes in solution as studied by aluminum-27 nuclear magnetic resonance","volume":"73","author":"Haraguchi","year":"1969","journal-title":"J. Phys. Chem."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"244","DOI":"10.1016\/j.jmr.2008.03.001","article-title":"MAS NMR spectra of quadrupolar nuclei in disordered solids: The Czjzek model","volume":"192","author":"Fretigny","year":"2008","journal-title":"J. Magn. Resonance"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/16\/2\/1240\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:55:06Z","timestamp":1760219706000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/16\/2\/1240"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2011,1,28]]},"references-count":42,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2011,2]]}},"alternative-id":["molecules16021240"],"URL":"https:\/\/doi.org\/10.3390\/molecules16021240","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2011,1,28]]}}}