![]() Die NMR-Spektren in Kombination mit spektraler Anpassung wurden ausführlich analysiert und bestimmte Parameter wie Zellulosegehalt und Kristallinität, Allomorph-Zusammensetzung und Querabmessungen für Zellulose-Elementarfibrillen und -Mikro-fibrillen wurden bestimmt. Ein Referenzspektrum von nicht-zellulosehaltigen Tabakbestandteilen wurde vom Spektrum jeder Probe subtrahiert, um ein Subspektrum der Zellulose-Bestandteile zu erhalten. Įs wurde eine neue Methode mit 13C-CP/MAS-NMR-Spektren (kernmagnetische Resonanz mit Kreuzpolarisation/Rotation um den magischen Winkel) für die gleichzeitige Mengenbestimmung und Strukturanalyse von Tabakzellulose nach der Extraktion mit Heißwasser oder saurem Lösungsmittel entwickelt. Therefore, this NMR method could provide important information on both amount and structure of cellulose in tobacco. The lateral dimensions for cellulose elementary fibrils and microfibrils were in the range of 3.0-6.0 nm and 6.0-13.0 nm, respectively. The cellulose crystallinity calculated by the spectral fitting in C4 -region was about 50%. The structure results obtained by the spectral fitting for the cellulose C1-region showed that the main allomorph composition in tobacco cellulose was Ip. The quantitative results showed that the average recovery was 94.0% with a relative standard deviation (RSD) of 4.6-4.8%. The NMR spectra in combination with spectral fitting were analyzed in detail and some parameters, such as the content of cellulose, crystallinity, allomorph composition and lateral dimensions for cellulose elementary fibrils and microfibrils were determined. A reference spectrum of tobacco noncellulose components was subtracted from the spectrum of each sample to obtain a sub-spectrum of the cellulose components. Xiaolan Zhu1, Ya Dai2, Changguo Wang2, and Lanlan Tan2ġ Research Center of Tobacco and Health, University of Science and Technology of China, Hefei 230052, ChinaĢ Technology Center of China Tobacco Chuanyu Industrial Corporation, Chengdu 610066, ChinaĪ new method utilizing 13C cross-polarization/magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) spectra was developed for the simultaneous quantitative determination and structure analysis of tobacco cellulose from hot water or acid detergent extraction. Quantitative and Structure Analysis of Cellulose in Tobacco by 13C CP / MAS NMR Spectroscopy * Lond.Beiträge zur Tabakforschung International/ Contributions to Tobacco Research Volume 27 "The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis." Proc. Schafer, " Discrete-Time Signal Processing," Prentice-Hall Signal Processing Series, 2 ed., 1999. Hilbert spectral analysis method is an important part of Hilbert–Huang transform. This frequency-time distribution of the amplitude is designated as the Hilbert amplitude spectrum, or simply Hilbert spectrum. It also enables us to represent the amplitude and the instantaneous frequency as functions of time in a three-dimensional plot, in which the amplitude can be contoured on the frequency-time plane. ![]() This equation gives both the amplitude and the frequency of each component as functions of time. Hilbert spectral analysis is a signal analysis method applying the Hilbert transform to compute the instantaneous frequency of signals according to
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