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Tytuł:
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An inexpensive apparatus for up to 97% continuous-flow parahydrogen enrichment using liquid helium.
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Autorzy:
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Du Y; Department of Chemistry, University of Florida, Gainesville, FL 32611, United States.
Zhou R; Department of Chemistry, University of Florida, Gainesville, FL 32611, United States.
Ferrer MJ; Department of Chemistry, University of Florida, Gainesville, FL 32611, United States.
Chen M; Department of Chemistry, Iowa State University, Ames, IA 50011, United States.
Graham J; Department of Physics, University of Florida, Gainesville, FL 32611, United States.
Malphurs B; Department of Physics, University of Florida, Gainesville, FL 32611, United States.
Labbe G; Department of Physics, University of Florida, Gainesville, FL 32611, United States.
Huang W; Department of Chemistry, Iowa State University, Ames, IA 50011, United States; Ames Laboratory, U.S. Department of Energy, Ames, IA 50011, United States.
Bowers CR; Department of Chemistry, University of Florida, Gainesville, FL 32611, United States; National High Magnetic Field Laboratory, University of Florida, Gainesville, FL 32611, United States. Electronic address: .
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Źródło:
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Journal of magnetic resonance (San Diego, Calif. : 1997) [J Magn Reson] 2020 Dec; Vol. 321, pp. 106869. Date of Electronic Publication: 2020 Nov 04.
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Typ publikacji:
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Journal Article
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Język:
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English
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Imprint Name(s):
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Publication: 2004- : San Diego : Elsevier
Original Publication: San Diego : Academic Press, c1997-2004.
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Contributed Indexing:
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Keywords: Hyperpolarization; PASADENA; PHIP; Parahydrogen; SABRE
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Entry Date(s):
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Date Created: 20201116 Latest Revision: 20201204
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Update Code:
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20240105
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DOI:
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10.1016/j.jmr.2020.106869
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PMID:
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33197680
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Nuclear spin hyperpolarization derived from parahydrogen can enable nuclear magnetic resonance spectroscopy and imaging with sensitivity enhancements exceeding four orders of magnitude. The NMR signal enhancement is proportional to 4x p -1, where x p is the parahydrogen mole fraction. For convenience, many labs elect to carry out the ortho-para conversion at 77 K where 50% enrichment is obtained. In theory, enrichment to 100% yields an automatic three-fold increase in the NMR signal enhancement. Herein, construction and testing of a simple and inexpensive continuous-flow converter for high para-enrichment is described. During operation, the converter is immersed in liquid helium contained in a transport dewar of the type commonly found in NMR labs for filling superconducting magnets. A maximum enrichment of 97.3±1.9% at 30 K was observed at 4.5 bar and 300 mL/min flow rate. The theoretically predicted 2.9-fold increase in the signal enhancement factor was confirmed in the heterogeneous hydrogenation of propene to propane over a PdIn/SBA-15 catalyst. The relatively low-cost to construct and operate this system could make high parahydrogen enrichment, and the associated increase in the parahydrogen-derived NMR signals, more widely accessible.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020. Published by Elsevier Inc.)
