The combination of chemical specificity and non-destructive nature has made NMR and MRI indispensable technologies for a broad range of fields, including chemistry, materials, biology and medicine. However, sensitivity issues have remained a persistent challenge. Over several decades Pines and members of his research group have developed numerous ways to hyperpolarize the spins of atomic nuclei.
Their focus over the past two years has been on diamond crystals and an impurity called a nitrogen-vacancy NV center, in which optical and spin degrees of freedom are coupled. In earlier studies, Pines and his group demonstrated that a low-strength magnetic field could be used to transfer NV center electron spin polarization to nearby carbon nuclei, resulting in hyperpolarized nuclei.
This spin transference process -- called dynamic nuclear polarization -- had been used before to enhance NMR signals, but always in the presence of high-strength magnetic fields and cryogenic temperatures. Pines and his group eliminated these requirements by placing a permanent magnet near the diamond. By eliminating the need for even a weak magnetic field, we're now able to make direct measurements of the bulk sample with NMR. In their Nature Communications paper, Pines, King and the other co-authors say that hyperpolarized diamonds, which can be efficiently integrated into existing fabrication techniques to create high surface area diamond devices, should provide a general platform for polarization transfer.
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Science News. Journal Reference : Jonathan P. King, Keunhong Jeong, Christophoros C. Vassiliou, Chang S. Shin, Ralph H. Page, Claudia E. Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond. Said nucleus should be substantially absent from a liquid system used by said methods of the invention.
J Chem. J , T 1 -T 2 correlation Song et al. J Magn. Additionally, the diffusion or relaxation or a combination thereof or exchange or combination ordered spectroscopy technique may include in a non-limiting manner spin-echo, stimulated echo, symmetric or asymmetric bipolar stimulated echo, symmetric or asymmetric bipolar LED, convection compensated and all variants of relaxation experiments. J Maga. The width of the peak or signal is measured in Hz. Without the use of a liquid system of the invention the peak width of compounds in a mixture, may be between to Hz.
This value range is considered to be broad thereby not permitting accurate differentiation of the components of the sample. Upon using a liquid system of the invention in accordance with a method of the invention, the peak width may be minimized or narrowed by at least to times compared to a suspension system comprising silica particulate, corresponding to peak width not greater than 0. In another one of its aspects the invention provides a kit comprising at least one container comprising at least one polar component; at least one non-polar component and at least one surfactant component; wherein said components are substantially 1 H-NMR inactive; and optionally instructions and means for their use in carrying out a liquid state diffusion ordered spectroscopy.
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In one embodiment of said kit, at least one container comprising components of liquid system of the invention may be an NMR tube possibly dispensable , which may be sealed. In some other embodiments, said means comprised in said kit include for example: an NMR tube, a spatula for adding the solid sample and a pipette or syringe for transferring the liquid, a container with a built in transfer mechanism for placing into an NMR tube.
In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:. Arrow pointing to separation between signals of hexamethyl disiloxane and DSS due to the use of defined microemulsion. The present invention provides a method for analyzing mixtures of compounds by 2D-NMR spectroscopy.
The method separates the compounds spectroscopically using differences in their diffusion characteristics in a liquid system of the invention. A liquid system of the invention is capable of increasing the separation in the diffusion dimension using a stable, completely liquid system while maintaining full resolution typical of a regular high-resolution NMR experiment, without resorting to solid-state techniques.
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Without being bound by theory it should be mentioned that the use of a liquid system of the invention for differential dissolution of a mixture comprising at least two compounds having different dissolution properties, and subjecting such a mixture to diffusion ordered spectroscopy has several advantages over the use of a suspension comprising solid particles such as silica, such as for example: easier control of droplet size in an emulsion formulation as opposed to particle size in a suspension , the magnetic susceptibility of emulsion droplets in a system of the invention is closer to the magnetic susceptibility of typical solvents, therefore no predetermination of components of the system to be defined prior to the execution of a diffusion ordered experiment of a sample is needed.
The line-width of a signal in a DOSY spectrum of a sample comprising a mixture is much less dependent on the magnetic susceptibility difference between the phases as compared to suspensions comprising silica particles. Variable temperature experiments can be carried out for a single sample and additionally, liquid systems of the invention are stable. In a preliminary 19 F self-diffusion measurements, a mixture of four compounds having different polar properties was used:.
For aqueous phase fractions less than 0. The amphiphilic flourosurfactant is located persistently at the interface between the oily and aqueous phases. In the pure oily and pure aqueous phases at the ends of the dilution line, the fluorosurfactant forms its own micelles. This indicates that it is preferentially located in the oily phase or at the interface of the oily droplets. The perflourohexane consistently diffuses rapidly indicating that it has no preference to oil or water and that it interacts only weakly with the solvent. Another exemplary liquid system of the invention is a microemulsion comprising isopropanol, water, perfluorododecanoic acid and its lithium and sodium salts and 1-bromoperfluoroheptane.
The suitability of these microemulsions for diffusion ordered NMR spectroscopy was tested with a sample mixture comprising hexamethyl disiloxane non-polar compound and DSS trimethylpentane sulfonic acid sodium salt polar compound. The spectrum in FIG. A similar strong effect has also been observed FIG. Effective date : Year of fee payment : 4. In a preliminary 19 F self-diffusion measurements, a mixture of four compounds having different polar properties was used: a non-polar perflourohexane C 6 F 14 , a polar sparingly soluble in water 2,4-dinitrofluorobenzene C 6 H 3 FN 2 O 4 , an amphiphilic fluorosurfactant FSN and highly polar and water soluble fluoride.
This mixture was tested with a liquid system comprising: one phase oily comprising Tween R -limonine:ethanol and a second phase aqueous comprising water:propylene glycol WO and Kogan et al. The invention claimed is: 1. A homogeneous liquid system, comprising: at least one polar component;. The liquid system according to claim 1 , wherein the at least one polar component comprises at least one solvent selected from the group consisting of water; a straight, branched, saturated, unsaturated or aromatic C 1 -C 20 alcohol; and any combinations thereof, the at least one solvent being substantially fully deuterated, perhalogenated or any combination thereof.
The liquid system according to claim 1 , wherein the at least one polar component is selected from the group consisting of D 2 O, isopropanol-d 8 , methanol-d 4 , ethanol-d 6 , 2,2,2-trifluoroethanol-d 3 , tertbutanol-d 10 ethylene glycol-d 6 , propylene glycol-d 8 , glycerol-d 8 , and any combination thereof. The liquid system according to claim 1 , wherein the at least one non-polar component comprises at least one hydrocarbon being substantially fully deuterated, perhalogenated, or any combination thereof selected from the group consisting of straight, branched, cyclic or polycyclic C 1 -C alkane, alkene or alkyne; a C 3 -C aromatic ring system, and any combination thereof.
The liquid system according to claim 1 , wherein the at least one non-polar component is selected from the group consisting of 1-bromoperfluoroheptane, 1-bromoperfluorooctane, perfluorohexane, perfluoroheptane, perfluorooctane, perfluorocyclohexane, and any combination thereof. The liquid system according to claim 1 , wherein the at least one surfactant component comprises at least one compound selected from the group consisting of an anionic, a cationic, a zwitterionic, and a non-ionic, surfactant being substantially fully deuterated, perhalogenated, or any combination thereof.
The liquid system according to claim 1 , wherein the at least one surfactant component is selected from the group consisting of perfluorohexanoate, perfluoroheptanoate, perfluorooctanoate, perfluorononoate, perfluorodecanoate, perfluoroundecanoate, perfluorododecanoate, perfluorotridecanoate, perfluorotetradecanoate, perfluoropentadecanoate, perfluorohexadecanoate, and any combination thereof. The liquid system according to claim 1 , being an emulsion, a microemulsion, a double emulsion, or any combination thereof, or any other type of micro- or nanostructured liquid.
The liquid system according to claim 1 , wherein the at least one polar component comprises D 2 O and at least one fully deuterated alcohol.
The liquid system according to claim 1 , wherein the at least one non-polar component comprises at least perhalogenated hydrocarbon. The liquid system according to claim 1 , wherein the at least one surfactant component comprises at least one perfluorinated or haloperfluorinated surfactant. A method of enhancing the diffusion separation of a mixture of at least two compounds, the method comprising: a providing a liquid system according to claim 1 ; and b mixing the system with the mixture of at least two compounds. A method for at least one of: generating a diffusion ordered spectrum of a mixture comprising at least two compounds, and.
The method according to claim 14 , further comprising the step of selecting a liquid system, being substantially devoid of at least one NMR active nucleus present in the mixture.
Enhancing carbon NMR signals in liquids | Max Planck Institute for Biophysical Chemistry
A kit comprising at least one container comprising a liquid system according to claim 1 ; and optionally instructions and means for their use in carrying out a liquid state diffusion ordered spectroscopy. USP true Liquid compositions and uses thereof for generating diffusion ordered nmr spectra of mixtures. Liquid compositions and uses thereof for generating diffusion ordered NMR spectra of mixtures. USB2 en. WOA1 en. EPA1 en. A method of and apparatus for inverting three-dimensional fluid property distribution over the t1,t2,d domain from nmr measurements.
JPA en. FRA1 en. Analysis of a sample placed in a support which allows diffusion of the constituents by nuclear magnetic resonance spectroscopy. Compositions, methods of preparing amino acids, and nuclear magnetic resonance spectroscopy. WOA2 en.
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Method for the magnetic resonance measurement of water-soluble sample molecules in molecular receptacles, for example in inverse micelles. Barjat, et al. Bilia, et al. Birlirakis, et al. Buevich, et al. Callaghan, et al. Gozansky, et al. B, , pp. Hoffman, et al. Jerschow, et al. A, , pp. Kogan, et al. Morris, et al.
Nilsson, et al.
Related NMR of Ordered Liquids
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