Relayed hyperpolarization for zero-field nuclear magnetic resonance.

Van Dyke, Erik T; Eills, James; Picazo-Frutos, Román; Sheberstov, Kirill F; Hu, Yinan; Budker, Dmitry; Barskiy, Danila A · Sci Adv · 2022

basic_science · Level V

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Abstract

Zero- to ultralow-field nuclear magnetic resonance (ZULF NMR) is a rapidly developing form of spectroscopy that provides rich spectroscopic information in the absence of large magnetic fields. However, signal acquisition still requires a mechanism for generating a bulk magnetic moment for detection, and the currently used methods only apply to a limited pool of chemicals or come at prohibitively high cost. We demonstrate that the parahydrogen-based SABRE (signal amplification by reversible exchange)-Relay method can be used as a more general means of generating hyperpolarized analytes for ZULF NMR by observing zero-field <i>J</i>-spectra of [<sup>13</sup>C]-methanol, [1-<sup>13</sup>C]-ethanol, and [2-<sup>13</sup>C]-ethanol in both <sup>13</sup>C-isotopically enriched and natural abundance samples. We explore the magnetic field dependence of the SABRE-Relay efficiency and show the existence of a second maximum at 19.0 ± 0.3 mT. Despite presence of water, SABRE-Relay is used to hyperpolarize ethanol extracted from a store-bought sample of vodka (%<i>P</i><sub>H</sub> ~ 0.1%).