NMR spectroscopy with compact instruments

Singh, Kawarpal; Blümich, Bernhard

doi:10.1016/j.trac.2016.02.014

Cited by 84 publications

(61 citation statements)

References 75 publications

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“…However, traditional high-resolution NMR spectrometers are hardly applied to industrial process control due to their open magnetic field, large size and high price and the required cryogen use. Recently developed low-field benchtop spectrometers with permanent magnets (up to 2 T) are less expensive and more compact and provide sufficient accuracy for chemical analysis, making them competitive with traditional high-resolution spectrometers [11,12]. A compact NMR spectrometer was applied to the determination of several quality parameters of diesel fuel in the paper by Killner et al [13].…”

Section: Introductionmentioning

confidence: 99%

“…However, TD-NMR has proven usable in industrial applications due to its mobility, low price, robustness, non-destructive analysis, and lack of sample preparation [11,15,16]. Furthermore, online process monitoring by NMR is also an increasingly used technique [11,12,17]. In one study [18], the TD-NMR technique was applied to the online determination of metal ion precipitation in mine water and was subsequently tested in a mine environment.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

Nikolskaya

Hiltunen

2018

Appl Magn Reson

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An approach based on time-domain nuclear magnetic resonance (TD-NMR) enables the estimation of the molecular properties of fatty acid mixtures-kinematic viscosity (µ), heating value (δ), cetane number (CN), and carbon chain length (CL). In this approach, the 1 H NMR spin-spin relaxation rates R 2 or times T 2 were used to determine these molecular properties. Online monitoring of the µ, δ, CN, and CL of fatty acid mixtures was performed using an online TD-NMR system that had been modified for flowing samples. The presented results show the potential of TD-NMR for online quality control during the production of liquid fuels.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

Nikolskaya

Hiltunen

2018

Appl Magn Reson

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“…Wax leaching. a) Representative low‐field 1 H NMR spectrum of n ‐hexane containing wax extracted from factory‐grade LDPE pellets measured with a 1 T Spinsolve NMR device at room temperature. The very good magnetic field homogeneity of this sensor enables acquiring spectral information.…”

Section: Resultsmentioning

confidence: 99%

Impact of Exposure Conditions on the Morphology of Polyethylene by Compact NMR

Teymouri

Adams

Blümich

2018

Macromolecular Symposia

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Today many polyethylene (PE) products are employed in long‐term applications that require the use of elevated temperatures and/or contact with different solvents. Both the exposure to heat and solvents can result in morphological changes, compromising the mechanical stability of the material. Disentangling morphological changes induced by either type of exposure and understanding their combined effect is crucial for establishing reliable structure‐property relationships. This, in turn, requires sensitive analytical methods that can probe the complex morphology of PE both in the laboratory and on site. Among existing analytical methods, NMR with compact devices have recently become a key analytical tool for the detailed morphological characterization of a variety of solid polymers including PE. This current work reviews the potential of compact NMR for monitoring and quantifying morphological changes in PE exposed to the aforementioned external conditions. To prove the reliability of compact proton NMR relaxation measurements, the results are compared with data from conventional high‐field proton wide‐line NMR spectroscopy, DSC, and FTIR spectroscopy. It could be shown that simple, static proton relaxation measurements garner detailed information about the exposure‐induced morphological changes through the quantification of phase composition and chain dynamics. Moreover, the NMR method has a key advantage over other methods, because the chain mobility of the soft amorphous phase is a very sensitive microscopic parameter under exposure conditions. The various presented examples and the good agreement of the NMR results with those of other analytical methods show that low‐field NMR is a promising option for in‐situ aging studies.

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“…NMR plays a particularly important role in food chemistry where it used in the study of both simple organic molecules and complex macromolecular structures and their complexes (Minoja, Napoli, 2014;Singh, Blümich, 2016;Hore, 2017) [1,13,16]. A large number of articles discuss the use of NMR for research of food products; meat, fish, dairy products, vegetables, fruits, juices, pastry, cheese, starch, honey and alcohol products (Minoja, [1,2,11,12,14,15,[17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Effects of the water desalting by reverse osmosis on the process of formation of water-alcohol mixtures. 1H NMR spectroscopy studies

Кузьмин¹,

Suikov²,

Нєміріч³

et al. 2017

Ukr. food j.

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Introduction. The aim of the publication is to study the effect of demineralising of the water by reverse osmosis on the drift of protons of ethanol and water, as well as the stabilization these systems by 1 H NMR spectroscopy. Materials and methods.1 H NMR analysis was conducted with the usage of the following: FT-NMR Bruker Avance II spectrometer (400 MHz); specially shaped capillary with acetoned 6 ; high accuracy ampoules № 507-HP; dispenser; ethyl rectified spirit (ERS); demineralized water by reverse osmosis; wateralcohol mixtures (WAM) from ERS and demineralized water.Results and discussion. In this paper, we have established some new features in the process of creating WAM that are directly dependent on the demineralization of water by reverse osmosis. The drift of protons of ethanol and water in the process of creating WAM indicates the complex dynamic of the system stabilization processes. A «restoration» of location of hydroxyl proton's signal (OH) of ethanol is not observed during the time interval of 0 to 432 h after the mixing, with a constant alcohol concentration (WAM's strength -39,92 % vol.) and system's temperature control (t=23,5 ºC). A characteristic feature of ethanol (EtOH) and water (H 2 O) hydroxyl protons in the WAM during the interval of τ=12-432 h is that the signals (δ EtОН =4,93-5,01 ppm; δ Н2O =4,33-4,41 ppm.) located separately from each other with a difference in a chemical shifts of Δδ=0,59-0,61 ppm. Division of the signals related to the process of reconstruction of water structure that was destroyed by demineralization by reverse osmosis and to set an equilibrated structure of new system. The low exchange rate (separately observed signals of hydroxyl and water) can be related to a significant microheterogeneity of the system and the corresponding barrier effect that reduces the effective rate of protons' exchange.Conclusion. Experimentally, using the method of 1 H NMR spectroscopy, the influence of the use of reverse osmosis of water treatment on the spectral characteristics of mobile protons of ethanol and water, as well as the stabilization of the system in the process of creation of water-alcohol mixtures, was established. It is shown that for such systems, the stabilization process of the water-alcohol mixture is simultaneously with the restoration of a network of hydrogen bonds in the aqueous phase of the microheterogeneous medium. ─── Food Technology ─── ───

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NMR spectroscopy with compact instruments

Cited by 84 publications

References 75 publications

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

Impact of Exposure Conditions on the Morphology of Polyethylene by Compact NMR

Effects of the water desalting by reverse osmosis on the process of formation of water-alcohol mixtures. 1H NMR spectroscopy studies

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