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Quasi-Resonance Signal Amplification by Reversible Exchange.

Publication ,  Journal Article
Theis, T; Ariyasingha, NM; Shchepin, RV; Lindale, JR; Warren, WS; Chekmenev, EY
Published in: The journal of physical chemistry letters
October 2018

Here we present the feasibility of NMR signal amplification by reversible exchange (SABRE) using radio frequency irradiation at low magnetic field (0.05 T) in the regime where the chemical shifts of free and catalyst-bound species are similar. In SABRE, the 15N-containing substrate and parahydrogen perform simultaneous chemical exchange on an iridium hexacoordinate complex. A shaped spin-lock induced crossing (SLIC) radio frequency pulse sequence followed by a delay is applied at quasi-resonance (QUASR) conditions of 15N spins of a 15N-enriched substrate. As a result of this pulse sequence application, 15N z-magnetization is created from the spin order of parahydrogen-derived hyperpolarized hydrides. The repetition of the pulse sequence block consisting of a shaped radio frequency pulse and the delay leads to the buildup of 15N magnetization. The modulation of this effect by the irradiation frequency, pulse duration and amplitude, delay duration, and number of pumping cycles was demonstrated. Pyridine-15N, acetonitrile-15N, and metronidazole-15N2-13C2 substrates were studied representing three classes of compounds (five- and six-membered heterocycles and nitrile), showing the wide applicability of the technique. Metronidazole-15N2-13C2 is an FDA-approved antibiotic that can be injected in large quantities, promising noninvasive and accurate hypoxia sensing. The 15N hyperpolarization levels attained with QUASR-SABRE on metronidazole-15N2-13C2 were more than 2-fold greater than those with SABRE-SHEATH (SABRE in shield enables alignment transfer to heteronuclei), demonstrating that QUASR-SABRE can deliver significantly more efficient means of SABRE hyperpolarization.

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Published In

The journal of physical chemistry letters

DOI

EISSN

1948-7185

ISSN

1948-7185

Publication Date

October 2018

Volume

9

Issue

20

Start / End Page

6136 / 6142

Related Subject Headings

  • 51 Physical sciences
  • 34 Chemical sciences
  • 03 Chemical Sciences
  • 02 Physical Sciences
 

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Theis, T., Ariyasingha, N. M., Shchepin, R. V., Lindale, J. R., Warren, W. S., & Chekmenev, E. Y. (2018). Quasi-Resonance Signal Amplification by Reversible Exchange. The Journal of Physical Chemistry Letters, 9(20), 6136–6142. https://doi.org/10.1021/acs.jpclett.8b02669
Theis, Thomas, Nuwandi M. Ariyasingha, Roman V. Shchepin, Jacob R. Lindale, Warren S. Warren, and Eduard Y. Chekmenev. “Quasi-Resonance Signal Amplification by Reversible Exchange.The Journal of Physical Chemistry Letters 9, no. 20 (October 2018): 6136–42. https://doi.org/10.1021/acs.jpclett.8b02669.
Theis T, Ariyasingha NM, Shchepin RV, Lindale JR, Warren WS, Chekmenev EY. Quasi-Resonance Signal Amplification by Reversible Exchange. The journal of physical chemistry letters. 2018 Oct;9(20):6136–42.
Theis, Thomas, et al. “Quasi-Resonance Signal Amplification by Reversible Exchange.The Journal of Physical Chemistry Letters, vol. 9, no. 20, Oct. 2018, pp. 6136–42. Epmc, doi:10.1021/acs.jpclett.8b02669.
Theis T, Ariyasingha NM, Shchepin RV, Lindale JR, Warren WS, Chekmenev EY. Quasi-Resonance Signal Amplification by Reversible Exchange. The journal of physical chemistry letters. 2018 Oct;9(20):6136–6142.
Journal cover image

Published In

The journal of physical chemistry letters

DOI

EISSN

1948-7185

ISSN

1948-7185

Publication Date

October 2018

Volume

9

Issue

20

Start / End Page

6136 / 6142

Related Subject Headings

  • 51 Physical sciences
  • 34 Chemical sciences
  • 03 Chemical Sciences
  • 02 Physical Sciences