title: Generating long-lasting 1H and 13C hyperpolarization in small molecules with parahydrogen-induced polarization.
abstract: Recently, Levitt and co-workers demonstrated that conserving the population of long-lasting nuclear singlet states in weak magnetic fields can lead to a preservation of nuclear spin information over times substantially longer than governed by the (high-field) spin-lattice relaxation time T1. Potential benefits of the prolonged spin information for magnetic resonance imaging and spectroscopy were pointed out, particularly when combined with the parahydrogen induced polarization (PHIP) methodology. In this contribution, we demonstrate that an increase of the effective relaxation time by a factor up to three is achieved experimentally, when molecules hyperpolarized by PHIP are kept in a weak magnetic field instead of the strong field of a typical NMR magnet. This increased lifetime of spin information makes the known PHIP phenomena more compatible with the time scales of biological processes and, thus, more attractive for future investigations.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstrasse 12, 53115 D-Bonn, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Jonischkeit
authors.forename: Ute
authors.initials: U
authors.lastname: Bommerich
authors.forename: Jörg
authors.initials: J
authors.lastname: Stadler
authors.forename: Klaus
authors.initials: K
authors.lastname: Woelk
authors.forename: Heiko G
authors.initials: HG
authors.lastname: Niessen
authors.forename: Joachim
authors.initials: J
authors.lastname: Bargon