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}
Pub Date : 2024-11-07DOI: 10.1016/j.jmro.2024.100173
Ilia B. Moroz, Neta Katzav, Asya Svirinovsky-Arbeli, Michal Leskes
In this protocol we outline the practical aspects and methodology for performing metal ions-based dynamic nuclear polarization (MI-DNP), focusing on materials science applications. In MI-DNP polarization is transferred from unpaired electrons of paramagnetic metal ions to nearby nuclear spins, thereby increasing the sensitivity of NMR spectroscopy. The protocol encompasses detailed steps for (i) selecting suitable metal ion dopant based on chemical, structural and electron paramagnetic resonance (EPR) considerations, (ii) characterizing the concentration, homogeneity and EPR properties of the dopant and (iii) performing the MI-DNP experiment itself, including optimization of the field position and reliable assessment of the DNP enhancement factors. By adhering to this protocol, the interested reader can implement the MI-DNP approach in an efficient way, facilitating spectroscopic studies of functional materials.
{"title":"A practical guide to metal ions dynamic nuclear polarization in materials science","authors":"Ilia B. Moroz, Neta Katzav, Asya Svirinovsky-Arbeli, Michal Leskes","doi":"10.1016/j.jmro.2024.100173","DOIUrl":"10.1016/j.jmro.2024.100173","url":null,"abstract":"<div><div>In this protocol we outline the practical aspects and methodology for performing metal ions-based dynamic nuclear polarization (MI-DNP), focusing on materials science applications. In MI-DNP polarization is transferred from unpaired electrons of paramagnetic metal ions to nearby nuclear spins, thereby increasing the sensitivity of NMR spectroscopy. The protocol encompasses detailed steps for (i) selecting suitable metal ion dopant based on chemical, structural and electron paramagnetic resonance (EPR) considerations, (ii) characterizing the concentration, homogeneity and EPR properties of the dopant and (iii) performing the MI-DNP experiment itself, including optimization of the field position and reliable assessment of the DNP enhancement factors. By adhering to this protocol, the interested reader can implement the MI-DNP approach in an efficient way, facilitating spectroscopic studies of functional materials.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100173"},"PeriodicalIF":2.624,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653620","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 : 2024-10-28DOI: 10.1016/j.jmro.2024.100171
Nele Reimets, Kerti Ausmees, Indrek Reile
Non-hydrogenative PHIP (nh-PHIP) is an NMR signal enhancement technique that offers several orders of magnitude gains in detection sensitivity. It is one of the few hyperpolarization methods that have been demonstrated to be applicable to chemical analysis of biological samples and potentially metabolomics. It is, however, a chemoselective method and needs to be tuned to particular analyte and metabolite classes at a time.
Herein, we present a systematic study where we apply four nh-PHIP modifications to urine samples from two different species – human and dog. Firstly, this allows to explore the whole analyte class scope and present what information is nh-PHIP capable of providing by varying the composition of the nh-PHIP catalyst system and the sample preparation protocol. Secondly, comparing hyperpolarized spectra from urines from different species demonstrates that this hyperpolarization technique is robust and tolerant of possibly considerable matrix differences: signals of the same metabolites appear at same chemical shifts from urines that differ from one-another much more than is likely in a realistic metabolomics study. Thereby we propose the idea that nh-PHIP is ready for application in metabolomics experiments.
{"title":"Current state of the art of analyte scope in urine metabolome analysis by non-hydrogenative PHIP","authors":"Nele Reimets, Kerti Ausmees, Indrek Reile","doi":"10.1016/j.jmro.2024.100171","DOIUrl":"10.1016/j.jmro.2024.100171","url":null,"abstract":"<div><div>Non-hydrogenative PHIP (nh-PHIP) is an NMR signal enhancement technique that offers several orders of magnitude gains in detection sensitivity. It is one of the few hyperpolarization methods that have been demonstrated to be applicable to chemical analysis of biological samples and potentially metabolomics. It is, however, a chemoselective method and needs to be tuned to particular analyte and metabolite classes at a time.</div><div>Herein, we present a systematic study where we apply four nh-PHIP modifications to urine samples from two different species – human and dog. Firstly, this allows to explore the whole analyte class scope and present what information is nh-PHIP capable of providing by varying the composition of the nh-PHIP catalyst system and the sample preparation protocol. Secondly, comparing hyperpolarized spectra from urines from different species demonstrates that this hyperpolarization technique is robust and tolerant of possibly considerable matrix differences: signals of the same metabolites appear at same chemical shifts from urines that differ from one-another much more than is likely in a realistic metabolomics study. Thereby we propose the idea that nh-PHIP is ready for application in metabolomics experiments.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"21 ","pages":"Article 100171"},"PeriodicalIF":2.624,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142587184","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 : 2024-10-10DOI: 10.1016/j.jmro.2024.100169
D. Panariti , B.J. Bayard , A. Barbon , Y.E. Kandrashkin , P.K. Poddutoori , A. van der Est , M. Di Valentin
Photoexcited triplet states of porphyrins are of great relevance in various applications due to their high yield, long lifetime, and strong electron spin polarization. This study delves into properties and spin dynamics of the triplet state of a series of hypervalent phosphorus(V) porphyrins. Transient Electron Paramagnetic Resonance (TrEPR) measurements, supported by quantum chemical calculations as well as by optical absorption/luminescence experiments, reveal that, unlike singlet states, the lowest triplet state does not exhibit charge-transfer (CT) character upon photoexcitation. However, the presence of excited CT singlet states alters the intersystem crossing in phosphorus(V) porphyrins, leading to a sign change in the initial multiplet polarization of the photoexcited triplet state. TrEPR results further demonstrate that significant net polarization develops in the triplet states of the phosphorus(V) porphyrins due to the dynamic Jahn-Teller effect. Yet, this effect remains largely unaffected by differences in their molecular structures.
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