Computer aided analysis of 13C n.m.r. spectra of multicomponent mixtures: 3. Analysis of individual components of a heavy gasoline from liquefaction of Polish coal

Matlengiewicz, Marek; Henzel, N.; Czachowska, Danuta; Schmit‐Quilès, F.; Nicole, D.; Lauer, Jean-Claude

doi:10.1016/0016-2361(94)90278-x

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…along with their convergence problems [10]. Consequently, several alternative approaches have been proposed in the last 20 years.…”

Section: O S S I E Rmentioning

confidence: 99%

“…Then, we may apply the previous measure in Equation (10) on the two marginals ofP (ω 1 , ω 2 ) along the two dimensions to obtainŴ 1 andŴ 2 . Now, the signal ε(n, m) is a white noise only if the two measures are less than a threshold λ α .…”

Section: -D Signalsmentioning

confidence: 99%

“…The Adaptive SubBand (ASB) decomposition associated to LPSVD will be called ASB-LPSVD. The results are compared to those given by a classical method which associates a classical FT approach with a maximum likelihood deconvolution algorithm (FT+DCONV) [10,61]. The latter is used in the best possible conditions, that is it makes use of the entire signal and, during the deconvolution process, the exact number of components K (which is perfectly known, K = 104) is used.…”

Section: -D Nmrmentioning

confidence: 99%

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NMR Data Analysis: A Time-Domain Parametric Approach Using Adaptive Subband Decomposition

Djermoune

Tomczak

Brie

2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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and available online here Cet article fait partie du dossier thématique ci-dessous publié dans la revue OGST, Vol. 69, n°2, et téléchargeable ici Résumé -Analyse de données RMN : une approche paramétrique basée sur une décomposi-tion en sous-bandes adaptative -Dans ce papier, nous proposons une méthode rapide d'analyse de signaux de spectroscopie de Résonance Magnétique Nucléaire (RMN), dans le cas Lorentzien, fondée sur une décomposition adaptative en sous-bandes. Cette dernière est obtenue par une succession d'étages de filtrage/décimation aboutissant à un arbre de décomposition. À chaque noeud de l'arbre, les paramètres du signal correspondant à la sous-bande sont estimés par une méthode haute-résolution. Puis l'erreur d'estimation est utilisée dans un test d'arrêt qui permet de décider si la décomposition doit être poursuivie ou non dans cette branche. Ainsi, cette approche permet la sélection automatique du niveau de décimation ce qui conduit la décomposition à s'adapter au contenu fréquentiel du signal. De plus, la méthode entraîne une réduction du temps de calcul et facilite le choix des paramètres libres comparativement à une analyse globale du signal. Son efficacité est illustrée au travers d'exemples de signaux RMN 13 C 1-D et 2-D.

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“…along with their convergence problems [10]. Consequently, several alternative approaches have been proposed in the last 20 years.…”

Section: O S S I E Rmentioning

confidence: 99%

Section: -D Signalsmentioning

confidence: 99%

Section: -D Nmrmentioning

confidence: 99%

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NMR Data Analysis: A Time-Domain Parametric Approach Using Adaptive Subband Decomposition

Djermoune

Tomczak

Brie

2013

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…For a relatively low concentration of particular components of the mixture and using a non-polar solvent for NMR measurements to avoid molecular interactions, the chemical shifts determined for the pure products are sufficiently stable and reproducible to be used to pinpoint the separate lines in the mixture. Analyses based on this principle have been conducted for mixtures of hydrocarbons [15], and it was shown by Casanova et al [16] that such an approach is also possible for the analysis of essential oils. It is, therefore, necessary to collect a library of spectra of the pure compounds and to analyse a mixture by comparison of the chemical shifts and relative intensities determined for the pure compounds with the respective lines for these compounds present in the mixtures.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Exploration of the possibility of combined HS-GC-MS and¹³C NMR spectroscopic investigation of the composition of the essential oils of selected sage(Salvia)species

Sajewicz¹,

Matlengiewicz²,

Rzepa³

et al. 2011

Acta Chromatographica

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The objective of this study was to explore the possibility of combining headspace gas chromatography with mass spectrometric detection (HS-GC-MS) and 13 C NMR spectroscopy to enhance the detectability of components of the essential oils of medicinal plants of the Salvia genus. Preliminary investigations were performed with two sage species, Salvia lavandulifolia and Salvia triloba, known for particularly abundant yields of their respective essential oils. By use of HS-GC-MS, characteristic fingerprints of the volatile fractions were obtained for plant species from two different vegetation seasons (2007 and 2008). Partial identification of the components of these volatile fractions was performed, and comparison of the chromatographic fingerprints confirmed seasonal fingerprint similarity within the same species. Preliminary 13 C NMR measurements resulted in well shaped spectra with an abundance of regularly distributed signals. This suggested the possibility of using 13 C NMR spectroscopy in phytochemical research, in parallel with HS-GC-MS, to enhance the detectability of volatile components of plant species belonging to this genus.

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“…The method was based on the deconvolution of the carbonyl signal in the 13 C NMR spectrum by means of the algorithm of maximum likelihood [2] and then by comparison of the intensities of the individual lines with those calculated according to 1 st order Markov statistics. However, in the case of a copolymer, due to the complexity of the spectrum this method permitted only assignment of the predominating sequences as it was shown for the copolymer of methyl methacrylate and ethyl acrylate [3], PMMA/EA.…”

Section: Introductionmentioning

confidence: 99%

Incremental method for determination of sequence distribution of poly(methyl methacrylate) by ¹³C NMR spectroscopy

1999

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IntroductionIn our previous paper [1] we have shown that it was possible to assign individual configurational sequences of poly(methyl methacrylate), PMMA, up to the heptad level. The method was based on the deconvolution of the carbonyl signal in the 13 C NMR spectrum by means of the algorithm of maximum likelihood [2] and then by comparison of the intensities of the individual lines with those calculated according to 1 st order Markov statistics. However, in the case of a copolymer, due to the complexity of the spectrum this method permitted only assignment of the predominating sequences as it was shown for the copolymer of methyl methacrylate and ethyl acrylate [3], PMMA/EA. Based on these first results we have developed a new method of incremental calculation of chemical shifts of the carbonyl signal for different configurational-compositional sequences at triad and pentad level. Therefore, having both intensities and respective line positions, we were able to simulate the 13 C NMR carbonyl signal for this copolymer [4]. Now, we would like to test if this incremental method is applicable to describe the carbonyl signal observed in the 13 C NMR spectrum of the model homopolymer, PMMA. ExperimentalPredominantly syndiotactic PMMA was synthesized by free radical polymerization. The methyl methacrylate monomer was placed in a double-coated reactor under nitrogen and then heated up to 78°C with azobisisobutyronitrile (AIBN) as radical initiator. Predominantly isotactic PMMA was prepared by anionic polymerization under argon atmosphere at -78°C in a mixture of toluene and tetrahydrofuran as a solvent, according to the method described previously [5], using fluorenyllithium as the initiator.The 100 MHz 13 C NMR spectra were recorded on a Bruker DRX 400 for 5 w. % solutions in CDCl 3 at 40°C. In order to obtain quantitative spectra a gated decoupling sequence was applied even though the nuclear Overhauser effect does not influence the carbonyl signal [6] and the time delay between the pulses has to be set at least 5 times greater than the longest relaxation time. Since T 1(C=O) ≅ 3 ÷ 6 sec, the delay was set to 30 sec [7]. A reasonable signal to noise ratio was attained after about 1200 scans. The quantitative nature of the spectra was verified by comparison of the intensities for the C=O, α-CH 3 and α-C signals. Results and discussion Syndiotactic PMMAIn the previous publication [4] we have shown that the 13 C NMR chemical shifts for different configurational sequences of PMMA/EA observed in the carbonyl signal can be described in an empirical manner. For example, the positions of the two symmetric methyl methacrylate triads can be calculated as: Sciences, Institute of Coal Chemistry, ul. Sowinskiego 5, Poland Abstract -A method of incremental calculation of chemical shifts in the 13 C NMR spectra for different configurational-compositional sequences, developed for copolymer of methyl methacrylate and ethyl acrylate, PMMA/EA, has been applied to poly(methyl methacrylate) samples of different tacticity. The numer...

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Computer aided analysis of 13C n.m.r. spectra of multicomponent mixtures: 3. Analysis of individual components of a heavy gasoline from liquefaction of Polish coal

Cited by 7 publications

References 9 publications

NMR Data Analysis: A Time-Domain Parametric Approach Using Adaptive Subband Decomposition

NMR Data Analysis: A Time-Domain Parametric Approach Using Adaptive Subband Decomposition

Exploration of the possibility of combined HS-GC-MS and¹³C NMR spectroscopic investigation of the composition of the essential oils of selected sage(Salvia)species

Incremental method for determination of sequence distribution of poly(methyl methacrylate) by ¹³C NMR spectroscopy

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Computer aided analysis of 13C n.m.r. spectra of multicomponent mixtures: 3. Analysis of individual components of a heavy gasoline from liquefaction of Polish coal

Cited by 7 publications

References 9 publications

NMR Data Analysis: A Time-Domain Parametric Approach Using Adaptive Subband Decomposition

NMR Data Analysis: A Time-Domain Parametric Approach Using Adaptive Subband Decomposition

Exploration of the possibility of combined HS-GC-MS and13C NMR spectroscopic investigation of the composition of the essential oils of selected sage(Salvia)species

Incremental method for determination of sequence distribution of poly(methyl methacrylate) by 13C NMR spectroscopy

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Product

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About

Exploration of the possibility of combined HS-GC-MS and¹³C NMR spectroscopic investigation of the composition of the essential oils of selected sage(Salvia)species

Incremental method for determination of sequence distribution of poly(methyl methacrylate) by ¹³C NMR spectroscopy