Recycling and Imaging of Nuclear Singlet Hyperpolarization

• Published in: Journal of the American Chemical Society Vol. 135; no. 13; pp. 5084 - 5088
• Main Authors: Pileio, Giuseppe, Bowen, Sean, Laustsen, Christoffer, Tayler, Michael C. D, Hill-Cousins, Joseph T, Brown, Lynda J, Brown, Richard C. D, Ardenkjaer-Larsen, Jan H, Levitt, Malcolm H
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 03-04-2013
• Subjects: Carbon Isotopes; Magnetic Resonance Spectroscopy
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja312333v

The strong enhancement of NMR signals achieved by hyperpolarization decays, at best, with a time constant of a few minutes. Here, we show that a combination of long-lived singlet states, molecular design, magnetic field cycling, and specific radiofrequency pulse sequences allows repeated observation of the same batch of polarized nuclei over a period of 30 min and more. We report a recycling protocol in which the enhanced nuclear polarization achieved by dissolution-DNP is observed with full intensity and then returned to singlet order. MRI experiments may be run on a portion of the available spin polarization, while the remaining is preserved and made available for a later use. An analogy is drawn with a “spin bank” or “resealable container” in which highly polarized spin order may be deposited and retrieved.