Proton nuclear magnetic resonance integration

Use of an integrated system incorporating CCC separation, PDA detector, and LC-MS proved to be a valuable tool in the rapid identification of known compounds from microbial extracts.6 This collection of analytical data has enabled us to make exploratory use of advanced data analysis methods to enhance the identification process. For example, from the UV absorbance maxima and molecular weight for the active compound(s) present in a fraction, a list of potential structural matches from a natural products database (e.g., Berdy Bioactive Natural Products Database, Dictionary of Natural Products by Chapman and Hall, etc.) can be generated. Subsequently, the identity of metabolite(s) was ascertained by acquiring a proton nuclear magnetic resonance ( H-NMR) spectrum. 

The overall blending stability of SMA in the material bulk and the surface grafting stability on material surfaces were examined by leaching tests and evaluated respectively with proton nuclear magnetic resonance spectroscopy [ H-NMR] and quantitative ATR-FT-IR. Firstly, SMA-MSPEO and SPEO with equivalent amounts of PEG components were respectively blended into PEU matrix materials. The initial quantity of PEG was measured and recorded by integrating the PEG-specific I-NMR peak areas at S = 3.52 ppm (- O - CH2 - CH2 - 0 -). The integral values were normalized... 

Traditionally, either gas chromatography combined with mass spectroscopy (GC-MS), density measurements, or refractometry is used to determine the relative concentration of the permeant mixtures [68]. However, proton nuclear magnetic resonance ( H NMR) is another excellent method to quantify concentrations because of its ease of use and high accuracy. The molar ratio of the mixture is calculated from the ratio of the integration of peaks corresponding to the components in the mixture. Once the ratios of permeants are known, selectivity can be calculated. To demonstrate that H NMR is an accurate method for determining the composition of liquid mixtures, a trial run was carried out using measured volumes of water and methanol (Fig. 33.17). 

The structures of vanicosides A (1) and B (2) and hydropiperoside (3) were established primarily by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy techniques and fast atom bombardment (FAB) mass spectrometry (MS).22 The presence of two different types of phenylpropanoid esters in 1 and 2 was established first through the proton (4H) NMR spectra which showed resonances for two different aromatic substitution patterns in the spectrum of each compound. Integration of the aromatic region defined these as three symmetrically substituted phenyl rings, due to three p-coumaryl moieties, and one 1,3,4-trisubstituted phenyl ring, due to a feruloyl ester. The presence of a sucrose backbone was established by two series of coupled protons between 3.2 and 5.7 ppm in the HNMR spectra, particularly the characteristic C-l (anomeric) and C-3 proton doublets... 

The hydrocarbon ("oil") fraction of a coal pyrolysis tar prepared by open column liquid chromatography (LC) was separated into 16 subfractions by a second LC procedure. Low voltage mass spectrometry (MS), infrared spectroscopy (IR), and proton (PMR) as well as carbon-13 nuclear magnetic resonance spectrometry (CMR) were performed on the first 13 subfractions. Computerized multivariate analysis procedures such as factor analysis followed by canonical correlation techniques were used to extract the overlapping information from the analytical data. Subsequent evaluation of the integrated analytical data revealed chemical information which could not have been obtained readily from the individual spectroscopic techniques. The approach described is generally applicable to multisource analytical data on pyrolysis oils and other complex mixtures. 

Nuclear Magnetic Resonance Spectra. Sad tier Research Laboratories, Philadelphia. Proton NMR spectra of more than 64,000 compounds. Peaks are assigned to the hydrogen nuclei responsible for the absorptions, and integration of the signals is shown on many of the spectra. 

Regiostructures for soluble poly(CHD) and its copolymers are determined by solution nuclear magnetic resonance (NMR) spectroscopy. For the poly(CHD) unit, the Ho, Ha, and Hb protons (Figure 18.2) are identified with signals at, respectively, 5.73, 2.01, and 1.56 ppm. There are equal numbers of Ho and Ha protons in the 1,4-unit of poly(CHD), while the ratio of Ho to Ha protons in the 1,2-unit is 2 3. Therefore, regioregularity can be estimated by the Ho/Ha integral value ratio. 

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