Dissolution Dynamic Nuclear Polarization of the 77Se Nucleus. Issue 2 (24th November 2022)

• Record Type: Journal Article
• Authors: Suh, Eul Hyun; Ratnakar, James; Singh, Jaspal; Kovacs, Zoltan
• Is Part Of: Analysis & Sensing. Volume 3:Issue 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-24
• Subjects: selenium -- 77Se NMR -- dynamic nuclear polarization -- hyperpolarization -- T1 relaxation; Chemistry, Analytic -- Periodicals; Analytical biochemistry -- Periodicals; 543
• DOI: 10.1002/anse.202200086
• Languages: English
• ISSNs: 2629-2742

Abstract

Abstract: 77 Se is a spin 1 / 2 ${{ 1/2 }}$, low sensitivity nucleus with a natural abundance of 7.6 %. Although 77 Se NMR is very useful in the characterization of selenium containing molecules including seleno‐proteins, the detection of 77 Se is challenging in biological samples without enrichment. Therefore, the goal of this work was to establish whether the 77 Se signal could be enhanced in the liquid state by dissolution dynamic nuclear polarization (DNP) NMR without the need of enrichment. The dominant spin‐lattice relaxation mechanism for 77 Se is via chemical shift anisotropy, which is highly dependent on the molecular symmetry. Here we tested three selenium compounds (sodium selenate, sodium selenite and selenocystine) with different molecular symmetries in dissolution DNP experiments and demonstrated that 77 Se DNP using commercially available hardware is feasible but the achieved NMR signal enhancements (1368‐fold for selenate, 125‐fold for selenite and no enhancement for selenocystine at 9.4 T) were strongly dependent on molecular symmetry. Abstract : Hyperpolarized 77 Se NMR signals were successfully detected in the liquid state after dissolution dynamic nuclear polarization (DNP) of sodium selenate and sodium selenite. However, the observed signal enhancement is strongly dependent on molecular structure reflecting the dominant chemical shift anisotropy (CSA) relaxation mechanism of 77 Se nuclear spins.