Communication
Relaxometry of insensitive nuclei: Optimizing dissolution dynamic nuclear polarization

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Abstract

We report measurements of spin-lattice relaxation of carbon-13 as a function of the magnetic field (‘relaxometry’) in view of optimizing dissolution-DNP. The sample is temporarily lifted into the stray field above a high-resolution magnet using a simple and inexpensive ‘shuttle’. The signals of arbitrary molecules can be observed at high field with high-resolution and sensitivity. During the dissolution process and subsequent ‘voyage’ from the polarizer to the NMR magnet, relaxation is accelerated by paramagnetic polarizing agents, but it can be quenched by using scavengers.

Graphical abstract

The scheme shows a dissolution-DNP polarizer and a 800 MHz NMR magnet. The hyperpolarized sample experiences very low fields during its transfer, which accelerates relaxation, thus inducing extra polarization losses.

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Research highlights

► We measured I1 of carbon-13 as a function of B0 in view of optimizing dissolution-DNP. ► The sample is lifted into the stray field above a high-resolution magnet using a simple “shuttle”. ► The signals of arbitrary molecules are observed at high field with high resolution and sensitivity. ► In dissolution-DNP relaxation occurs during the “voyage” from the polarizer to the NMR magnet. ► Relaxation can be limited by using scavengers or by sustaining the magnetic field during the sample “voyage”.

Section snippets

Acknowledgments

We thank Dr. Arnaud Comment and Prof. Jacques van der Klink at EPFL, and Dr. Ben van den Brandt, Dr. Ton Konter and Dr. Patrick Hautle at the Paul Scherrer Institute for the design and construction of the DNP polarizer. We gratefully acknowledge Prof. Lothar Helm and Dr. Fabien Ferrage for many stimulating discussions and Martial Rey and Roger Mottier for technical assistance. This work was supported by the Swiss National Science Foundation (Grant 200020-124694), the Commission pour la

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