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Titolo:
Effect of residual ashes on CPMAS-C-13 NMR spectra of humic substances from volcanic soils
Autore:
Conte, P; Piccolo, A; van Lagen, B; Buurman, P; Hemminga, MA;
Indirizzi:
Univ Naples, Dipartimento Sci Chim Agr, I-80055 Portici, Na, Italy Univ Naples Portici Na Italy I-80055 Chim Agr, I-80055 Portici, Na, Italy
Titolo Testata:
FRESENIUS ENVIRONMENTAL BULLETIN
fascicolo: 4, volume: 10, anno: 2001,
pagine: 368 - 374
SICI:
1018-4619(200104)10:4<368:EORAOC>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
MODEL ORGANIC-COMPOUNDS; DETERMINING QUANTITATION; CROSS POLARIZATION; MAGNETIC-MATERIALS; STATE; MOLECULES; SYSTEMS; REMOVAL;
Keywords:
volcanic soils; CPMAS C-13-NMR; cross-polarization time; proton spin-lattice relaxation time; molecular motions;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
17
Recensione:
Indirizzi per estratti:
Indirizzo: Piccolo, A Univ Naples, Dipartimento Sci Chim Agr, Via Univ 100, I-80055 Portici, Na,Italy Univ Naples Via Univ 100 Portici Na Italy I-80055 ici, Na,Italy
Citazione:
P. Conte et al., "Effect of residual ashes on CPMAS-C-13 NMR spectra of humic substances from volcanic soils", FR ENV BULL, 10(4), 2001, pp. 368-374

Abstract

Potentially paramagnetic elements such as Fe, Cu, and Mn, did not affect NMR sensitivity and T-1 rho(H) values of humic, materials from volcanic soils, despite a large ash content in the extracts. T-1 rho(H) values increasedwith increasing C/H ratios, thereby confirming a relationship between the number of protons bound to carbons and process of relaxation in solid humicmaterials. Differences in T-1 rho(H) values were explained by molecular com position of the samples, Few carbon-bound protons and high molecular rigidity in highly aromatic humic matter reduced the efficiency of the relaxation. Humic samples richer in polar carbons showed variable T-1 rho(H) valuesdue to different molecular rigidity conferred by intermolecular hydrogen bonds. Not only the number, but also the distribution of protons in humic molecules appeared to affect T-1 rho,(H) values.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 12:45:33