Determination of partition coefficients using 1 H NMR spectroscopy and time domain complete reduction to amplitude-frequency table (CRAFT) analysis

2017 ◽  
Vol 55 (8) ◽  
pp. 724-729 ◽  
Author(s):  
David Soulsby ◽  
Jeryl A. M. Chica
Keyword(s):  
Nmr Spectroscopy ◽  
Time Domain ◽  
Partition Coefficients ◽  
Complete Reduction ◽  
H Nmr ◽  
Frequency Table

Determination of the content of fatty acid methyl esters (FAME) in biodiesel samples obtained by esterification using 1 H-NMR spectroscopy

2008 ◽  
Vol 46 (11) ◽  
pp. 1051-1054 ◽  
Author(s):  
Vinicius M. Mello ◽  
Flavia C. C. Oliveira ◽  
William G. Fraga ◽  
Claudia J. do Nascimento ◽  
Paulo A. Z. Suarez
Keyword(s):  
Fatty Acid ◽  
Nmr Spectroscopy ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
H Nmr ◽  
Acid Methyl

scholarly journals Time-Domain Nuclear Magnetic Resonance (TD-NMR) and Chemometrics for Determination of Fat Content in Commercial Products of Milk Powder

2017 ◽  
Vol 100 (2) ◽  
pp. 330-334 ◽  
Author(s):  
Paloma Andrade Martins Nascimento ◽  
Paulo Lopes Barsanelli ◽  
Ana Paula Rebellato ◽  
Juliana Azevedo Lima Pallone ◽  
Luiz Alberto Colnago ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Time Domain ◽  
Pulse Sequence ◽  
Milk Powder ◽  
Nir Spectroscopy ◽  
Fat Content ◽  
Nondestructive Method ◽  
Multivariate Model ◽  
Analytical Frequency

Abstract This study shows the use of time-domain (TD)-NMR transverse relaxation (T2) data and chemometrics in the nondestructive determination of fat content for powdered food samples such as commercial dried milk products. Most proposed NMR spectroscopy methods for measuring fat content correlate free induction decay or echo intensities with the sample's mass. The need for the sample's mass limits the analytical frequency of NMR determination, because weighing the samples is an additional step in this procedure. Therefore, the method proposed here is based on a multivariate model of T2 decay, measured with Carr-Purcell-Meiboom-Gill pulse sequence and reference values of fat content. The TD-NMR spectroscopy method shows high correlation (r = 0.95) with the lipid content, determined by the standard extraction method of Bligh and Dyer. For comparison, fat content determination was also performed using a multivariate model with near-IR (NIR) spectroscopy, which is also a nondestructive method. The advantages of the proposed TD-NMR methodare that it (1) minimizes toxic residue generation, (2) performs measurements with high analytical frequency (a few seconds per analysis), and (3) does not require sample preparation (such as pelleting, needed for NIR spectroscopy analyses) or weighing the samples.

Enantiomeric NMR discrimination of carboxylic acids using actinomycin D as a chiral solvating agent

2019 ◽  
Vol 17 (6) ◽  
pp. 1466-1470 ◽  
Author(s):  
Liwen Bai ◽  
Pian Chen ◽  
Jiangxia Xiang ◽  
Jiarui Sun ◽  
Xinxiang Lei
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acids ◽  
Actinomycin D ◽  
H Nmr ◽  
Chiral Solvating Agent

We extended actinomycin D as a practical CSA for rapid enantiomeric determination of chiral carboxylic acids by1H NMR spectroscopy.

Chemical Shift Nonequivalence of Enantiomers of Amino Acid Derivatives in 1H NMR and 19F NMR Spectroscopy Induced by L-Chirasil- Val.

1992 ◽  
Vol 47 (7) ◽  
pp. 1034-1036 ◽  
Author(s):  
Bernhard Koppenhoefer ◽  
Michael Hummel
Keyword(s):  
Amino Acid ◽  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Methyl Esters ◽  
Enantiomeric Purity ◽  
Peak Splitting ◽  
H Nmr ◽  
Acid Methyl ◽  
Amino Acid Methyl Esters

Enantiomers of N-trifluoroacetyl-amino acid methyl esters in CC14 solution, after addition of the chiral polysiloxane (L)-Chirasil-Val, display a chemical shift nonequivalence ΔΔδ in both 1H NMR and 19F NMR spectroscopy. The effects found for the leucine and valine derivatives can be correlated with the thermodynamic parameters of interaction in the undiluted system, as determined by gas chromatography. In CDC13 solution, no peak splitting was observed. The method is potentially useful for the determination of the enantiomeric purity of substrates of low volatility.

Simultaneous determination of caffeine, gallic acid, theanine, (−)-epigallocatechin and (−)-epigallocatechin-3-gallate in green tea using quantitative1H-NMR spectroscopy

2014 ◽  
Vol 6 (3) ◽  
pp. 907-914 ◽  
Author(s):  
Yunfei Yuan ◽  
Yuelin Song ◽  
Wanghui Jing ◽  
Yitao Wang ◽  
Xiaoyun Yang ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Gallic Acid ◽  
Simultaneous Determination ◽  
Green Tea ◽  
Chemical Characterization ◽  
Tea Polyphenols ◽  
H Nmr

1H-NMR spectroscopy is utilized for chemical characterization along with simultaneous determination of caffeine, gallic acid, theanine and tea polyphenols, in commercial green tea.

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