title: Measuring absolute spin polarization in dissolution-DNP by Spin PolarimetrY Magnetic Resonance (SPY-MR).
abstract: Dynamic nuclear polarization at 1.2 K and 6.7 T allows one to achieve spin temperatures on the order of a few millikelvin, so that the high-temperature approximation (ΔE<kT) is violated for the nuclear Zeeman interaction ΔE=γB0h/(2π) of most isotopes. Provided that, after rapid dissolution and transfer to an NMR or MRI system, the hyperpolarized molecules contain at least two nuclear spins I and S with a scalar coupling JIS, the polarization of spin I (short for 'investigated') can be determined from the asymmetry AS of the multiplet of spin S (short for 'spy'), provided perturbations due to second-order (strong coupling) effects are properly taken into account. If spin S is suitably discreet and does not affect the relaxation of spin I, this provides an elegant way of measuring spin polarizations 'on the fly' in a broad range of molecules, thus obviating the need for laborious measurements of signal intensities at thermal equilibrium. The method, dubbed Spin PolarimetrY Magnetic Resonance (SPY-MR), is illustrated for various pairs of (13)C spins (I, S) in acetate and pyruvate.
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. Electronic address: basile.vuichoud@epfl.ch.
authors.forename: Basile
authors.initials: B
authors.lastname: Vuichoud
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Jonas
authors.initials: J
authors.lastname: Milani
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Chappuis
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Bornet
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Ecole Normale Supérieure-PSL Research University, Département de Chimie, 24 rue Lhomond, 75005 Paris, France; Sorbonne Universités, UPMC Paris 06, LBM, 4 place Jussieu, 75005 Paris, France; CNRS, UMR 7203 LBM, 75005 Paris, France.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Bodenhausen
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Bruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland. Electronic address: sami.jannin@epfl.ch.
authors.forename: Sami
authors.initials: S
authors.lastname: Jannin
keywords: Direct measurement of polarization; Dissolution Dynamic Nuclear Polarization; Hyperpolarization; NMR spectroscopy; Spin temperature; Spy spin