An Apparatus for Production of Isotopically and Spin-Enriched Hydrogen for Induced Polarization Studies

Gamliel, Ayelet; Allouche‐Arnon, Hyla; Nalbandian, Ruppen; Barzilay, Claudia M.; Gomori, John M.; Katz‐Brull, Rachel

doi:10.1007/s00723-010-0161-9

Cited by 34 publications

(59 citation statements)

References 28 publications

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“…A repetition time of 300 ms was used between scans. This duration is sufficiently larger than the T 1 of oH 2 , which is reported as being between 3 ms and 15 ms, 27 to allow for quantitative analysis. 256 scans were acquired, resulting in an total acquisition time of 77 s.…”

Section: Methodsmentioning

confidence: 99%

“…The chamber for the enrichment of pH 2 content was of similar design to that reported previously in the literature. 4,27 Briefly, it consisted of a copper coil (C) (OD = 9.5 mm, ID = 7.7 mm, L = 3 m) packed with charcoal (Sigma-Aldrich), which was submerged in a Dewar (D) filled with liquid nitrogen. The charcoal was held in place with Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…15,16,21,27 The sample was placed in a bench-top NMR spectrometer (Magritek Spinsolve) operating at a 1 H Larmor frequency of 43.5 MHz. A spectrum was recorded using a standard 90…”

Section: Methodsmentioning

confidence: 99%

“…One possible reason why x f pH2 does not reach the equilibrium value of 52.1 % expected for pH 2 fraction at liquid nitrogen temperatures, is that the gas flowing through the coil does not reach 77 K due to insufficient cooling. A value of 50.0 % for x f pH2 , instead suggests a slighter higher temperature of 80 K. Gamliel et al 27 also used a liquid nitrogen cooled pH 2 generator (although with an iron(III) oxide catalyst), and used NMR spectroscopy to measure x pH2 of the resulting enriched gas. They reported a slow increase in x pH2 over time, with 42.3 % reached after around 2 h, increasing to 46.3 % after 3.7 h. This is broadly similar to the rate of increase shown in Figure 3.…”

Section: At-line and On-line Monitoring Of Generator Performancementioning

confidence: 99%

“…16 However, the ortho isomer is NMR visible, and the x pH2 can be calculated by taking the ratio of peak area from an unknown sample to that of a known sample (at the same gas density), usually nH 2 . 15,16,21,27 Therefore, the NMR method only requires a single reference sample, and no further calibration is needed. Figure 5 compares the NMR spectra of a tube filled with nH 2 and pH 2 enriched H 2 at 4 bar.…”

Section: Comparison and Validation With Nmr Measurementsmentioning

confidence: 99%

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Quantitative In Situ Monitoring of Parahydrogen Fraction Using Raman Spectroscopy

Parrott

Dallin²,

Andrews³

et al. 2018

Appl Spectrosc

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Raman spectroscopy has been used to provide a rapid, non-invasive and non-destructive quantification method for determining the parahydrogen fraction of hydrogen gas. The basis of the method is the measurement of the ratio of the first two rotational bands of hydrogen at 355 cm −1 and 586 cm −1 corresponding to parahydrogen and orthohydrogen, respectively. The method has been used to determine the parahydrogen content during a production process and a reaction. In the first example, the performance of an in-house liquid nitrogen cooled parahydrogen generator was monitored both at-line and on-line. The Raman measurements showed that it took several hours for the generator to reach steady state and hence, for maximum parahydrogen production (50 %) to be reached. The results obtained using Raman spectroscopy were compared to those obtained by at-line low-field NMR spectroscopy. While the results were in good agreement, Raman analysis has several advantages over NMR for this application. The Raman method does not require a reference sample, as both spin isomers (ortho and para) of hydrogen can be directly detected, which simplifies the procedure and eliminates some sources of error. In the second example, the method was used to monitor the fast conversion of parahydrogen to orthohydrogen in-situ. Here the ability to acquire Raman spectra every 30 s enabled a conversion process with a rate constant of 27.4 × 10 −4 s −1 to be monitored. The Raman method described here represents an improvement on previously reported work, in that it can be easily applied on-line and is approximately 500 times faster. This offers the potential of an industrially compatible method for determining parahydrogen content in applications that require the storage and usage of hydrogen.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…15,16,21,27 The sample was placed in a bench-top NMR spectrometer (Magritek Spinsolve) operating at a 1 H Larmor frequency of 43.5 MHz. A spectrum was recorded using a standard 90…”

Section: Methodsmentioning

confidence: 99%

Section: At-line and On-line Monitoring Of Generator Performancementioning

confidence: 99%

Section: Comparison and Validation With Nmr Measurementsmentioning

confidence: 99%

See 3 more Smart Citations

Quantitative In Situ Monitoring of Parahydrogen Fraction Using Raman Spectroscopy

Parrott

Dallin²,

Andrews³

et al. 2018

Appl Spectrosc

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Parawasserstoff‐basierte Hyperpolarisierung für die Biomedizin

et al. 2018

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Die Magnetresonanz (MR) von Kernspins ist einer der nützlichsten physikalischen Effekte für die humane Bildgebung, ebenso wie für die Aufklärung von molekularen Strukturen und die chemische Analyse. Das volle Potential der MR kann jedoch kaum genutzt werden, da nur ein geringer Bruchteil aller Kernspins polarisiert, sprich in einem äußeren magnetischen Feld ausgerichtet werden. Hyperpolarisierungsmethoden versuchen, die Polarisierung und damit das MR‐Signal auf anderem Wege zu erhöhen. Eine einzigartige Quelle reiner Spinordnung ist das langlebige, verschränkte Kernspin‐Singulett‐Isomer des Wasserstoffmoleküls, genannt Parawasserstoff (pH2). Mithilfe dieser “Spinordnung auf Abruf” kann das MR‐Signal um mehrere Größenordnungen verstärkt werden, wenn pH2 in Kontakt mit einem anderen Molekül gebracht wird. In Bezug auf eine biomedizinische Anwendung von pH2‐hyperpolarisierten Kontrastmitteln haben in den letzten zehn Jahren beeindruckende Fortschritte stattgefunden. Das Ziel dieses Aufsatzes ist es, diese Entwicklungen in den Bereichen der Spinphysik, Katalyse, Instrumentierung, Kontrastmittel und Anwendungen gebündelt und verständlich darzustellen.

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Parawasserstoff‐induzierte Hyperpolarisation von Gasen

et al. 2020

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Die Bildgebung von Gasen stellt eine große Herausforderung dar, ob per MRT oder mit anderen Methoden. NMR‐ und MRT‐Signale sind direkt proportional zur Kernspindichte und zur Kernspinpolarisation (Ausrichtungsgrad der Kernspins bzgl. eines angelegten Magnetfeldes). Die Kernspinpolarisation ist unter typischen Bedingungen sehr niedrig, z. B. ist die Polarisation bei 1.5 T und einer physiologisch relevanten Temperatur nur ein hunderttausendstel der maximal erreichbaren Polarisation. Daher wird MRT in erster Linie zur Bildgebung von Wasser, welches in Gewebe in hoher Konzentration vorliegt, herangezogen. Hyperpolarisationsmethoden erhöhen vorübergehend die Kernspinpolarisation bis zu einem Polarisationsgrad von maximal eins, was eine Signalverstärkung von mehreren Größenordnungen bedeutet. Dies ermöglicht 3D‐Bildgebung von weniger konzentrierten Analyten, wie etwa Biomolekülen oder Gasen. Parawasserstoff‐induzierte Polarisation (PHIP) kann sehr schnell erzielt werden. Zudem sind die verwendeten Verfahren leicht skalierbar und relativ kostengünstig. In diesem Kurzaufsatz fassen wir ausgewählte Neuerungen im Bereich der Parawasserstoff‐induzierten Polarisation zusammen, die in Zukunft zu neuen, inhalierbaren Kontrastmitteln führen können.

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An Apparatus for Production of Isotopically and Spin-Enriched Hydrogen for Induced Polarization Studies

Cited by 34 publications

References 28 publications

Quantitative In Situ Monitoring of Parahydrogen Fraction Using Raman Spectroscopy

Quantitative In Situ Monitoring of Parahydrogen Fraction Using Raman Spectroscopy

Parawasserstoff‐basierte Hyperpolarisierung für die Biomedizin

Parawasserstoff‐induzierte Hyperpolarisation von Gasen

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