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Titolo:
MALDI-TOF mass spectrometry of polyflavonoid tannins
Autore:
Pasch, H; Pizzi, A; Rode, K;
Indirizzi:
Deutsch Kunststoff Inst Darmstadt, D-64289 Darmstadt, Germany Deutsch Kunststoff Inst Darmstadt Darmstadt Germany D-64289 adt, Germany Univ Nancy 1, ENSTIB, F-88000 Epinal, France Univ Nancy 1 Epinal France F-88000 ncy 1, ENSTIB, F-88000 Epinal, France
Titolo Testata:
POLYMER
fascicolo: 18, volume: 42, anno: 2001,
pagine: 7531 - 7539
SICI:
0032-3861(200108)42:18<7531:MMSOPT>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
LASER-DESORPTION IONIZATION; INDUCED RADICAL AUTOCONDENSATION; COMPARATIVE KINETICS; SYNTHETIC-POLYMERS; PARTICLEBOARD; ADHESIVES; C-13-NMR;
Keywords:
MALDI; mass spectrometry; polyflavonoids;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
19
Recensione:
Indirizzi per estratti:
Indirizzo: Pasch, H Deutsch Kunststoff Inst Darmstadt, Schlossgartenstr 6, D-64289 Darmstadt, Germany Deutsch Kunststoff Inst Darmstadt Schlossgartenstr 6 Darmstadt Germany D-64289
Citazione:
H. Pasch et al., "MALDI-TOF mass spectrometry of polyflavonoid tannins", POLYMER, 42(18), 2001, pp. 7531-7539

Abstract

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight OL (MALDI-TOF) appears to be a suitable method for examining polyflavonoid tannin oligomers. It appears capable to determine aspects of the structure and characteristics of polyflavonoid tannins, which are otherwise too difficult to determine by other techniques. It has been possible to determine by MALDI-TOF for the two major industrial polyflavonoid tannins which exist, namely mimosa and quebracho tannins, and some of their modified derivatives that: (i) mimosa tannin is predominantly composed of prorobinetinidins while quebracho ispredominantly composed of profisetinidins, that (ii) mimosa tannin is heavily branched due to the presence of considerable proportions of 'angular' units in its structure while quebracho tannin is almost completely linear. These structural differences also contribute to the considerable differencesin viscosity of water solutions of the two tannins. (iii) the interflavonoid link is more easily hydrolysable, and does appear to sometime hydrolyse in quebracho tannin and profisetinidins, partly due to the linear structureof this tannin, and confirming NMR findings that this tannin is subject topolymerisation/depolymerisation equilibria. This showed that the decrease of viscosity due to acid/base treatments to yield tannin adhesive intermediates does also depend in quebracho from a certain level of hydrolysis of the tannin itself and not only of the carbohydrates present in the extract. This tannin hydrolysis does not appear to occur in mimosa tannin in which the interflavonoid Link is completely stable to hydrolysis. (iv) sulphitationhas been shown to influence the detachment of catechol B-rings much more than pyrogallol-type B-rings. (vi) the distribution of tannin oligomers, andthe tannins number average degree of polymerisation obtained by MALDI-TOF appear to compare well with the results obtained by other techniques. (C) 2001 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/09/20 alle ore 07:37:39