title: Milli-tesla NMR and spectrophotometry of liquids hyperpolarized by dissolution dynamic nuclear polarization.
abstract: Hyperpolarization methods offer a unique means of improving low signal strength obtained in low-field NMR. Here, simultaneous measurements of NMR at a field of 0.7mT and laser optical absorption from samples hyperpolarized by dissolution dynamic nuclear polarization (D-DNP) are reported. The NMR measurement field closely corresponds to a typical field encountered during sample injection in a D-DNP experiment. The optical spectroscopy allows determination of the concentration of the free radical required for DNP. Correlation of radical concentration to NMR measurement of spin polarization and spin-lattice relaxation time allows determination of relaxivity and can be used for optimization of the D-DNP process. Further, the observation of the nuclear Overhauser effect originating from hyperpolarized spins is demonstrated. Signals from (1)H and (19)F in a mixture of trifluoroethanol and water are detected in a single spectrum, while different atoms of the same type are distinguished by J-coupling patterns. The resulting signal changes of individual peaks are indicative of molecular contact, suggesting a new application area of hyperpolarized low-field NMR for the determination of intermolecular interactions.
authors.affiliation: Chemistry Department, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Chemistry Department, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA.
authors.forename: Chia-Hsiu
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Chemistry Department, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA.
authors.forename: Zechariah
authors.initials: Z
authors.lastname: Wilson
authors.affiliation: New Mexico Consortium, 100 Entrada Drive, Los Alamos, NM 87544, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Savukov
authors.affiliation: Chemistry Department, Texas A&M University, 3255 TAMU, College Station, TX 77843, USA. Electronic address: chilty@tamu.edu.
authors.forename: Christian
authors.initials: C
authors.lastname: Hilty
keywords: Dissolution dynamic nuclear polarization; Low-field NMR; Polarimetry; Relaxometry