Pub Date : 2024-12-10DOI: 10.1016/j.jmro.2024.100179
Wolfgang Kilian , Samira Gulich , Thomas Riemer , Lorenz Mitschang
The use of hyperpolarized media in combination with benchtop NMR spectrometers is currently extensively investigated to enable cost effective but highly sensitive applications. In this work, the instrumentation for the use of hyperpolarized 129Xe gas on a commercial benchtop-NMR spectrometer in a fully controllable yet automated mode is presented. A continuous-flow 129Xe polarizer is operated inline with the benchtop spectrometer. While the adjustment of the xenon gas partial pressure in the range of mbar to bar as well as the volume flow through the NMR sample is facilitated by the polarizer’s mass-flow controllers and two back-pressure regulators, respectively, the gas flow towards the NMR sample in situ in the benchtop magnet is time-controlled within the spectrometer’s RF pulse sequence programming. A calibration procedure for the gas flow control as well as thermally polarized xenon gas standards are introduced for quantification of the absolute 129Xe polarization. In this way, the 129Xe polarization achieved in the NMR measurement is determined in the 50% to 5% regime for very lean 1 mbar to high 500 mbar xenon partial pressure, respectively – in the optimum a more than 250,000-fold increase in comparison to thermal polarization. Such instrumentation may be implemented by combining any of the well-established continuous-flow 129Xe polarizer with any of the commercial benchtop spectrometers, thus facilitating high-performance hyperpolarized 129Xe benchtop NMR studies.
{"title":"Hyperpolarized 129Xe for benchtop NMR: Inline instrumentation for automated yet flexible operation yielding high polarization","authors":"Wolfgang Kilian , Samira Gulich , Thomas Riemer , Lorenz Mitschang","doi":"10.1016/j.jmro.2024.100179","DOIUrl":"10.1016/j.jmro.2024.100179","url":null,"abstract":"<div><div>The use of hyperpolarized media in combination with benchtop NMR spectrometers is currently extensively investigated to enable cost effective but highly sensitive applications. In this work, the instrumentation for the use of hyperpolarized <sup>129</sup>Xe gas on a commercial benchtop-NMR spectrometer in a fully controllable yet automated mode is presented. A continuous-flow <sup>129</sup>Xe polarizer is operated inline with the benchtop spectrometer. While the adjustment of the xenon gas partial pressure in the range of mbar to bar as well as the volume flow through the NMR sample is facilitated by the polarizer’s mass-flow controllers and two back-pressure regulators, respectively, the gas flow towards the NMR sample in situ in the benchtop magnet is time-controlled within the spectrometer’s RF pulse sequence programming. A calibration procedure for the gas flow control as well as thermally polarized xenon gas standards are introduced for quantification of the absolute <sup>129</sup>Xe polarization. In this way, the <sup>129</sup>Xe polarization achieved in the NMR measurement is determined in the 50% to 5% regime for very lean 1<!--> <!-->mbar to high 500<!--> <!-->mbar xenon partial pressure, respectively – in the optimum a more than 250,000-fold increase in comparison to thermal polarization. Such instrumentation may be implemented by combining any of the well-established continuous-flow <sup>129</sup>Xe polarizer with any of the commercial benchtop spectrometers, thus facilitating high-performance hyperpolarized <sup>129</sup>Xe benchtop NMR studies.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100179"},"PeriodicalIF":2.624,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1016/j.jmro.2024.100181
Reiya Yabuki , Koki Nishimura , Yuta Sawada , Masaaki Fuki , Yasuhiro Kobori , Nobuhiro Yanai
Chemically induced dynamic electron polarization (CIDEP) generates radical electron spins with high polarization at room temperature by quenching the photo-excited state of chromophores, which is useful for microwave-free optical dynamic nuclear polarization (DNP) in solution. While nitroxyl (TEMPO) radicals are typically used for this purpose, we show that a tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivative shows greater electron spin polarization than TEMPO by CIDEP using porphyrin chromophores. This is attributed to the longer spin-lattice relaxation time of TTM radicals, with a contribution of efficient quenching of chromophore photo-excited state by energy transfer from the triplet state of porphyrins to the doublet state of the TTM radicals. The porphyrin-TTM pair shows a larger nuclear spin polarization under continuous laser excitation than the porphyrin-TEMPO pair because of the larger polarization and longer spin-lattice relaxation time of the TTM radical electron spins. This work demonstrates the first example of in-solution CIDEP and optically-driven DNP using TTM radicals, opening new opportunities in a wide range of biological and medical applications.
{"title":"Dynamic electron and nuclear spin polarization in solution using porphyrin and tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivatives","authors":"Reiya Yabuki , Koki Nishimura , Yuta Sawada , Masaaki Fuki , Yasuhiro Kobori , Nobuhiro Yanai","doi":"10.1016/j.jmro.2024.100181","DOIUrl":"10.1016/j.jmro.2024.100181","url":null,"abstract":"<div><div>Chemically induced dynamic electron polarization (CIDEP) generates radical electron spins with high polarization at room temperature by quenching the photo-excited state of chromophores, which is useful for microwave-free optical dynamic nuclear polarization (DNP) in solution. While nitroxyl (TEMPO) radicals are typically used for this purpose, we show that a tris(2,4,6-trichlorophenyl)-methyl (TTM) radical derivative shows greater electron spin polarization than TEMPO by CIDEP using porphyrin chromophores. This is attributed to the longer spin-lattice relaxation time of TTM radicals, with a contribution of efficient quenching of chromophore photo-excited state by energy transfer from the triplet state of porphyrins to the doublet state of the TTM radicals. The porphyrin-TTM pair shows a larger nuclear spin polarization under continuous laser excitation than the porphyrin-TEMPO pair because of the larger polarization and longer spin-lattice relaxation time of the TTM radical electron spins. This work demonstrates the first example of in-solution CIDEP and optically-driven DNP using TTM radicals, opening new opportunities in a wide range of biological and medical applications.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"22 ","pages":"Article 100181"},"PeriodicalIF":2.624,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.jmro.2024.100180
Shushu Gao , Jiamin Yuan , Fangxiu Ye , Zhiqiang Liu , Anming Zheng , Shutao Xu
Molecular sieves possess unique properties and have emerged as the predominant catalysts with shape selectivity in the petrochemical industry because of their well-defined pore architectures. However, the existence of a constrained pore surroundings of molecular sieves can limit intracrystalline diffusion, leading to underutilization of the active volume of the molecular sieve or rapid catalysts deactivation during catalytic processes. Moreover, the mechanism of adsorption and diffusion of molecules inside molecular sieves is crucial for the optimization and advancement of catalysts in heterogeneous catalysis. Due to the complexity of the diffusion process in molecular sieve materials, it is very necessary to develop characterization methods that are more sensitive and informative for studying the adsorption and diffusion of guests inside pores. Advancements in characterization techniques and theoretical calculations have led to a more profound comprehension of the adsorption and diffusion properties of molecular sieves at the microscopic scale. This article mainly summarizes the research progress of molecular adsorption and diffusion in molecular sieve materials using advanced 129Xe NMR, hyperpolarized (HP) 129Xe NMR, and pulsed-field gradient (PFG) NMR techniques in recent years and focuses on the principles of these techniques and applicability of the relationship of adsorption-diffusion using these techniques within several molecular sieve systems. Moreover, the effects of the topology and pore connectivity of molecular sieves on the adsorption and diffusion of guest molecules as well as the effects of intracrystalline diffusion on catalytic reactions are discussed.
{"title":"Applications of 129Xe and PFG NMR techniques on adsorption and diffusion of molecular sieve materials","authors":"Shushu Gao , Jiamin Yuan , Fangxiu Ye , Zhiqiang Liu , Anming Zheng , Shutao Xu","doi":"10.1016/j.jmro.2024.100180","DOIUrl":"10.1016/j.jmro.2024.100180","url":null,"abstract":"<div><div>Molecular sieves possess unique properties and have emerged as the predominant catalysts with shape selectivity in the petrochemical industry because of their well-defined pore architectures. However, the existence of a constrained pore surroundings of molecular sieves can limit intracrystalline diffusion, leading to underutilization of the active volume of the molecular sieve or rapid catalysts deactivation during catalytic processes. Moreover, the mechanism of adsorption and diffusion of molecules inside molecular sieves is crucial for the optimization and advancement of catalysts in heterogeneous catalysis. Due to the complexity of the diffusion process in molecular sieve materials, it is very necessary to develop characterization methods that are more sensitive and informative for studying the adsorption and diffusion of guests inside pores. Advancements in characterization techniques and theoretical calculations have led to a more profound comprehension of the adsorption and diffusion properties of molecular sieves at the microscopic scale. This article mainly summarizes the research progress of molecular adsorption and diffusion in molecular sieve materials using advanced <sup>129</sup>Xe NMR, hyperpolarized (HP) <sup>129</sup>Xe NMR, and pulsed-field gradient (PFG) NMR techniques in recent years and focuses on the principles of these techniques and applicability of the relationship of adsorption-diffusion using these techniques within several molecular sieve systems. Moreover, the effects of the topology and pore connectivity of molecular sieves on the adsorption and diffusion of guest molecules as well as the effects of intracrystalline diffusion on catalytic reactions are discussed.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100180"},"PeriodicalIF":2.624,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.jmro.2024.100178
Shubham Kumar Debadatta, Sheetal Kumar Jain
Nitrogen vacancy centers in diamonds are promising spin-based quantum sensors and qubits. These optically addressable paramagnetic point defects have the potential to allow efficient dynamic nuclear polarization (DNP) under ambient conditions due to their large electron spin polarization and long spin coherence time. NV-based DNP studies have shown significant sensitivity enhancement of 13C nuclear magnetic resonance (NMR). In this work, we present an analytical theory using a density matrix and average Hamiltonian theory for NV-13C spin system under varying magnetic fields, internal interaction strengths, and microwave irradiation parameters. We use a reduced basis approach under selective excitation of a single quantum transition in NV-center electron spin levels to derive the expressions for the matching conditions, effective Hamiltonian and polarization transfer frequency. Our results provide insight into the optimal experimental conditions for efficient DNP and the impact of the internal interactions on the DNP performance. The theoretical predictions are verified using numerical simulations.
{"title":"Dynamic nuclear polarization mechanism in isolated NV-centers at high magnetic fields","authors":"Shubham Kumar Debadatta, Sheetal Kumar Jain","doi":"10.1016/j.jmro.2024.100178","DOIUrl":"10.1016/j.jmro.2024.100178","url":null,"abstract":"<div><div>Nitrogen vacancy centers in diamonds are promising spin-based quantum sensors and qubits. These optically addressable paramagnetic point defects have the potential to allow efficient dynamic nuclear polarization (DNP) under ambient conditions due to their large electron spin polarization and long spin coherence time. NV-based DNP studies have shown significant sensitivity enhancement of <sup>13</sup>C nuclear magnetic resonance (NMR). In this work, we present an analytical theory using a density matrix and average Hamiltonian theory for NV-<sup>13</sup>C spin system under varying magnetic fields, internal interaction strengths, and microwave irradiation parameters. We use a reduced basis approach under selective excitation of a single quantum transition in NV-center electron spin levels to derive the expressions for the matching conditions, effective Hamiltonian and polarization transfer frequency. Our results provide insight into the optimal experimental conditions for efficient DNP and the impact of the internal interactions on the DNP performance. The theoretical predictions are verified using numerical simulations.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100178"},"PeriodicalIF":2.624,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The observation of half-integer quadrupolar nuclei, which represent 66 % of the NMR-active isotopes, is essential to understand the atomic-level structure of inorganic materials near the surfaces with applications in the field of catalysis, biomaterials and optoelectronics. For that purpose, we have recently introduced an efficient technique, which combines the sensitivity gain provided by indirect DNP (dynamic nuclear polarization) under MAS (magic-angle spinning) and the high resolution obtained by refocusing the second-order quadrupolar interaction (H. Nagashima et al., J. Phys. Chem. Lett. 15 (2024) 4858). This technique combines (i) a D-RINEPT (dipolar-mediated refocused INEPT) transfer, (ii) an MQMAS (multiple-quantum MAS) filter, and (iii) a QCPMG (quadrupolar Carr-Purcell Meiboom-Gill) detection. We explain the design of several variants of this pulse sequence and notably the selection of the coherence transfer pathways. In particular, the amplitudes of the coherence transfer pathways through the ±3Q coherence orders of the quadrupolar isotope can be equalized using a train of π-pulses selective of the central transition, instead of a z-filter. This equalization method has the advantage to limit the length of the phase cycles and to enhance slightly the signal intensity. Moreover, for spin-3/2 nuclei subject to moderate or large quadrupolar interactions, more efficient excitation and conversion of 3Q coherences are achieved using cosine-modulated long-pulses (cos-lp), instead of fast-amplitude-modulated (FAM) pulses. The performances of the different D-RINEPT-MQMAS-QCPMG variants are compared through the observation of 35Cl and 27Al isotopes without DNP in l-histidine hydrochloride and isopropylamine-templated microporous aluminophosphate (ipa-AlPO4–14), respectively, as well as the acquisition of DNP-enhanced high-resolution spectra of 11B and 17O nuclei near the surface of partially oxidized boron nitride supported on dendritic and fibrous nanosilica and γ-alumina enriched in 17O isotope using a slurrying approach. The spectra recorded for γ-alumina show that the slurrying method produces less disorder than grinding assisted by 17O-enriched water.
{"title":"MQMAS spectra of half-integer quadrupolar nuclei enhanced by indirect DNP","authors":"Hiroki Nagashima , Julien Trébosc , Olivier Lafon , Jean-Paul Amoureux","doi":"10.1016/j.jmro.2024.100177","DOIUrl":"10.1016/j.jmro.2024.100177","url":null,"abstract":"<div><div>The observation of half-integer quadrupolar nuclei, which represent 66 % of the NMR-active isotopes, is essential to understand the atomic-level structure of inorganic materials near the surfaces with applications in the field of catalysis, biomaterials and optoelectronics. For that purpose, we have recently introduced an efficient technique, which combines the sensitivity gain provided by indirect DNP (dynamic nuclear polarization) under MAS (magic-angle spinning) and the high resolution obtained by refocusing the second-order quadrupolar interaction (H. Nagashima et al.<em>, J. Phys. Chem. Lett.</em> 15 (2024) 4858). This technique combines (i) a <em>D</em>-RINEPT (dipolar-mediated refocused INEPT) transfer, (ii) an MQMAS (multiple-quantum MAS) filter, and (iii) a QCPMG (quadrupolar Carr-Purcell Meiboom-Gill) detection. We explain the design of several variants of this pulse sequence and notably the selection of the coherence transfer pathways. In particular, the amplitudes of the coherence transfer pathways through the ±3Q coherence orders of the quadrupolar isotope can be equalized using a train of π-pulses selective of the central transition, instead of a z-filter. This equalization method has the advantage to limit the length of the phase cycles and to enhance slightly the signal intensity. Moreover, for spin-3/2 nuclei subject to moderate or large quadrupolar interactions, more efficient excitation and conversion of 3Q coherences are achieved using cosine-modulated long-pulses (cos-lp), instead of fast-amplitude-modulated (FAM) pulses. The performances of the different <em>D</em>-RINEPT-MQMAS-QCPMG variants are compared through the observation of <sup>35</sup>Cl and <sup>27</sup>Al isotopes without DNP in <span>l</span>-histidine hydrochloride and isopropylamine-templated microporous aluminophosphate (ipa-AlPO<sub>4</sub>–14), respectively, as well as the acquisition of DNP-enhanced high-resolution spectra of <sup>11</sup>B and <sup>17</sup>O nuclei near the surface of partially oxidized boron nitride supported on dendritic and fibrous nanosilica and γ-alumina enriched in <sup>17</sup>O isotope using a slurrying approach. The spectra recorded for γ-alumina show that the slurrying method produces less disorder than grinding assisted by <sup>17</sup>O-enriched water.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100177"},"PeriodicalIF":2.624,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.jmro.2024.100174
Qing Yang , Hadi Lotfi , Michal Kern , Frederik Dreyer , Mazin Jouda , Jan. G. Korvink , Bernhard Blümich , Jens Anders
In this paper, we present the design and experimental validation of a miniaturized Overhauser dynamic nuclear polarization (ODNP) platform for both continuous-wave (CW) and pulsed DNP enhancement experiments at a field strength of 0.25 T. The platform is centered around chip-integrated nuclear magnetic resonance (NMR) and microwave (MW) electronics and further incorporates a custom-designed laser-engraved ODNP probe, providing phase-coherent radio frequency (RF) excitation, low-noise amplification and acquisition of NMR signals, MW frequency synthesis, MW signal modulation, and MW power amplification. An experimental validation using TEMPOL solutions with different concentrations demonstrates the functionality and good performance of the presented ODNP platform. A maximum enhancement of with CW pumping was achieved using a 500 nL 10 mM non-degassed TEMPOL solution in water, representing the largest enhancement achieved to date in a chip-based ODNP platform. We also include a preliminary comparison between CW pumping and pulsed pumping using TEMPOL solutions with different electron relaxation times (apparent and ). Our study indicates that, for a power-limited miniaturized ODNP platform, pulsed pumping can surpass CW pumping in power efficiency for a given average power when the solution possesses a sufficiently long electron spin-lattice relaxation time.
{"title":"A miniaturized dual-mode continuous-wave and pulsed pumping ODNP platform","authors":"Qing Yang , Hadi Lotfi , Michal Kern , Frederik Dreyer , Mazin Jouda , Jan. G. Korvink , Bernhard Blümich , Jens Anders","doi":"10.1016/j.jmro.2024.100174","DOIUrl":"10.1016/j.jmro.2024.100174","url":null,"abstract":"<div><div>In this paper, we present the design and experimental validation of a miniaturized Overhauser dynamic nuclear polarization (ODNP) platform for both continuous-wave (CW) and pulsed DNP enhancement experiments at a <span><math><msub><mrow><mi>B</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> field strength of 0.25<!--> <!-->T. The platform is centered around chip-integrated nuclear magnetic resonance (NMR) and microwave (MW) electronics and further incorporates a custom-designed laser-engraved ODNP probe, providing phase-coherent radio frequency (RF) excitation, low-noise amplification and acquisition of NMR signals, MW frequency synthesis, MW signal modulation, and MW power amplification. An experimental validation using TEMPOL solutions with different concentrations demonstrates the functionality and good performance of the presented ODNP platform. A maximum enhancement of <span><math><mrow><mo>−</mo><mn>92</mn></mrow></math></span> with CW pumping was achieved using a 500<!--> <!-->nL 10<!--> <!-->mM non-degassed TEMPOL solution in water, representing the largest enhancement achieved to date in a chip-based ODNP platform. We also include a preliminary comparison between CW pumping and pulsed pumping using TEMPOL solutions with different electron relaxation times (apparent <span><math><msub><mrow><mi>T</mi></mrow><mrow><msup><mrow><mn>1</mn><mi>e</mi></mrow><mrow><mo>∗</mo></mrow></msup></mrow></msub></math></span> and <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>2e</mi></mrow></msub></math></span>). Our study indicates that, for a power-limited miniaturized ODNP platform, pulsed pumping can surpass CW pumping in power efficiency for a given average power when the solution possesses a sufficiently long electron spin-lattice relaxation time.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100174"},"PeriodicalIF":2.624,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.jmro.2024.100176
Dudari B. Burueva , Sergey V. Sviyazov , Nikita V. Chukanov , Nazim R. Mustafin , Oleg G. Salnikov , Eduard Y. Chekmenev , Kirill V. Kovtunov , Igor V. Koptyug
Sodium [13C]formate was successfully hyperpolarized using parahydrogen-induced polarization by means of side-arm hydrogenation (PHIP-SAH). Allyl [13C]formate was hyperpolarized using homogeneous hydrogenation of the corresponding unsaturated precursor (propargyl [13C]formate) in acetone-d6 with parahydrogen. The observed proton polarization was estimated as 16.6 ± 0.6 % while achieving 80 % chemical conversion. The 1H-to-13C polarization transfer was performed using magnetic field cycling. The highest observed polarization for 13C nuclei was estimated as 1.7 ± 0.2 % and was obtained at 250 nT polarization transfer magnetic field. We demonstrate that the 13C hyperpolarization is retained during the hydrolysis of allyl [13C]formate and hyperpolarized sodium [13C]formate was produced with P13C of 0.4 ± 0.1 %.
{"title":"Hyperpolarization of [13C]formate using parahydrogen","authors":"Dudari B. Burueva , Sergey V. Sviyazov , Nikita V. Chukanov , Nazim R. Mustafin , Oleg G. Salnikov , Eduard Y. Chekmenev , Kirill V. Kovtunov , Igor V. Koptyug","doi":"10.1016/j.jmro.2024.100176","DOIUrl":"10.1016/j.jmro.2024.100176","url":null,"abstract":"<div><div>Sodium [<sup>13</sup>C]formate was successfully hyperpolarized using parahydrogen-induced polarization by means of side-arm hydrogenation (PHIP-SAH). Allyl [<sup>13</sup>C]formate was hyperpolarized using homogeneous hydrogenation of the corresponding unsaturated precursor (propargyl [<sup>13</sup>C]formate) in acetone-d<sub>6</sub> with parahydrogen. The observed proton polarization was estimated as 16.6 ± 0.6 % while achieving 80 % chemical conversion. The <sup>1</sup>H-to-<sup>13</sup>C polarization transfer was performed using magnetic field cycling. The highest observed polarization for <sup>13</sup>C nuclei was estimated as 1.7 ± 0.2 % and was obtained at 250 nT polarization transfer magnetic field. We demonstrate that the <sup>13</sup>C hyperpolarization is retained during the hydrolysis of allyl [<sup>13</sup>C]formate and hyperpolarized sodium [<sup>13</sup>C]formate was produced with P<sub>13C</sub> of 0.4 ± 0.1 %.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100176"},"PeriodicalIF":2.624,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.jmro.2024.100172
Karel Kouřil , Benno Meier
Hyperpolarization can boost the sensitivity of nuclear magnetic resonance. Other things being equal, a polarization increase by one order of magnitude leads to a time saving by two orders of magnitude. However, other things are rarely equal, and in this tutorial article we calculate how side effects of hyperpolarization, namely changes in duty cycle, dilution, and resolution, influence the net sensitivity and time savings of the (hyperpolarized) NMR experiment. The signal-to-noise ratio is calculated both in time- and frequency-domain for a sample at thermal equilibrium using the principle of reciprocity. The hyperpolarized time gain (HYTIGA) is calculated separately for concentration- and mass-limited samples. The article includes a detailed appendix on the measurement of the coil’s -factor.
{"title":"Hyperpolarization and sensitivity in nuclear magnetic resonance","authors":"Karel Kouřil , Benno Meier","doi":"10.1016/j.jmro.2024.100172","DOIUrl":"10.1016/j.jmro.2024.100172","url":null,"abstract":"<div><div>Hyperpolarization can boost the sensitivity of nuclear magnetic resonance. Other things being equal, a polarization increase by one order of magnitude leads to a time saving by two orders of magnitude. However, other things are rarely equal, and in this tutorial article we calculate how side effects of hyperpolarization, namely changes in duty cycle, dilution, and resolution, influence the net sensitivity and time savings of the (hyperpolarized) NMR experiment. The signal-to-noise ratio is calculated both in time- and frequency-domain for a sample at thermal equilibrium using the principle of reciprocity. The hyperpolarized time gain (HYTIGA) is calculated separately for concentration- and mass-limited samples. The article includes a detailed appendix on the measurement of the coil’s <span><math><mi>Q</mi></math></span>-factor.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100172"},"PeriodicalIF":2.624,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-09DOI: 10.1016/j.jmro.2024.100175
Max Filkins , Arthur Harrison , Guilhem J. Collier , Graham Norquay , Jim M. Wild , Sean P. Rigby , Galina E. Pavlovskaya , Thomas Meersmann
Pulmonary MRI of hyperpolarized xenon-129 (hp129Xe) dissolved in the lung parenchyma and vascular phase is gaining increasing attention for clinical assessment of gas exchange in multiple diseases. These conditions can involve thickening of barrier tissues due to fibrotic scarring or reduced capillary blood flow leading to diminished gas-blood exchange hence, the ratios between hp129Xe signals arising from the lung membrane (M), the red blood cells (RBC), and the gas phase hold significant diagnostic value. However, comparing hp129Xe signal ratios quantitatively across different studies may pose challenges due to varied experimental conditions and opted pulse sequence protocols.
A solution to this problem arises from materials science applications of hp129Xe where xenon dissolved in porous materials or polymers can display chemical shifts similar to the M and RBC shift in lungs. This work explored the generation of MR spectral profiles with respect to chemical shift and signal intensity ratios that closely resemble spectral profiles observed in human lungs in health and disease. At ambient temperatures, reticulated open cell polyurethane foam treated with olive oil as a fatty phase produced dissolved phase 129Xe chemical shifts of 215 ppm and 196 ppm, respectively, that emulate typical RBC and M signals. The uptake kinetics into the non-toxic materials was sufficiently similar to pulmonary signal uptake to enable hp129Xe MRI with dissolved phase ratios that closely resembled clinical data.
A phantom assembly was devised to allow for gas handling protocols that matched clinical protocols. The current iteration of the developed phantom enables rapid testing of basic experimental protocols and can be used for training purposes without regulatory approval and governance. Furthermore, the introduced concept shows a pathway for the development of a quantitative universal phantom standard for dissolved phase pulmonary hp129Xe MRI. A robust phantom standard will require materials with longer shelf lifetime than the oil-foam system used in this study and would benefit from a hierarchical porous network with more defined microstructure similar to that found in lungs.
{"title":"A standardized MRI phantom for dissolved phase 129Xe MRI","authors":"Max Filkins , Arthur Harrison , Guilhem J. Collier , Graham Norquay , Jim M. Wild , Sean P. Rigby , Galina E. Pavlovskaya , Thomas Meersmann","doi":"10.1016/j.jmro.2024.100175","DOIUrl":"10.1016/j.jmro.2024.100175","url":null,"abstract":"<div><div>Pulmonary MRI of hyperpolarized xenon-129 (hp<sup>129</sup>Xe) dissolved in the lung parenchyma and vascular phase is gaining increasing attention for clinical assessment of gas exchange in multiple diseases. These conditions can involve thickening of barrier tissues due to fibrotic scarring or reduced capillary blood flow leading to diminished gas-blood exchange hence, the ratios between hp<sup>129</sup>Xe signals arising from the lung membrane (M), the red blood cells (RBC), and the gas phase hold significant diagnostic value. However, comparing hp<sup>129</sup>Xe signal ratios quantitatively across different studies may pose challenges due to varied experimental conditions and opted pulse sequence protocols.</div><div>A solution to this problem arises from materials science applications of hp<sup>129</sup>Xe where xenon dissolved in porous materials or polymers can display chemical shifts similar to the M and RBC shift in lungs. This work explored the generation of MR spectral profiles with respect to chemical shift and signal intensity ratios that closely resemble spectral profiles observed in human lungs in health and disease. At ambient temperatures, reticulated open cell polyurethane foam treated with olive oil as a fatty phase produced dissolved phase <sup>129</sup>Xe chemical shifts of 215 ppm and 196 ppm, respectively, that emulate typical RBC and M signals. The uptake kinetics into the non-toxic materials was sufficiently similar to pulmonary signal uptake to enable hp<sup>129</sup>Xe MRI with dissolved phase ratios that closely resembled clinical data.</div><div>A phantom assembly was devised to allow for gas handling protocols that matched clinical protocols. The current iteration of the developed phantom enables rapid testing of basic experimental protocols and can be used for training purposes without regulatory approval and governance. Furthermore, the introduced concept shows a pathway for the development of a quantitative universal phantom standard for dissolved phase pulmonary hp<sup>129</sup>Xe MRI. A robust phantom standard will require materials with longer shelf lifetime than the oil-foam system used in this study and would benefit from a hierarchical porous network with more defined microstructure similar to that found in lungs.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100175"},"PeriodicalIF":2.624,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1016/j.jmro.2024.100170
Ruud L.E.G. Aspers, Marco Tessari
2D NMR zero-quantum spectroscopy offers a robust and convenient way to resolve hydride resonances in non-hydrogenative ParaHydrogen Induced Polarization experiments. This approach has been recently applied to the detection and quantification of dilute components in biofluids and natural extracts. For certain classes of analytes, however, modulation of the zero-quantum coherence occurs at several kiloHertz frequency, which determines long measurement times for attaining the desired resolution in the indirect dimension. Here, we propose an alternative 2D approach to measure high-resolution NMR spectra that affords enhanced sensitivity and reduced experimental time for optimal sample throughput.
{"title":"Improved 2D hydride detection for NMR-chemosensing via p‐H2 Hyperpolarization","authors":"Ruud L.E.G. Aspers, Marco Tessari","doi":"10.1016/j.jmro.2024.100170","DOIUrl":"10.1016/j.jmro.2024.100170","url":null,"abstract":"<div><div>2D NMR zero-quantum spectroscopy offers a robust and convenient way to resolve hydride resonances in non-hydrogenative ParaHydrogen Induced Polarization experiments. This approach has been recently applied to the detection and quantification of dilute components in biofluids and natural extracts. For certain classes of analytes, however, modulation of the zero-quantum coherence occurs at several kiloHertz frequency, which determines long measurement times for attaining the desired resolution in the indirect dimension. Here, we propose an alternative 2D approach to measure high-resolution NMR spectra that affords enhanced sensitivity and reduced experimental time for optimal sample throughput.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100170"},"PeriodicalIF":2.624,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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