Long lived Singlet Spin States originating from Parahydrogen stored at different magnetic fields.

MARÍA BELÉN FRANZONI

Workshop; COST WG3 Meeting; 2013

Parahydrogen Induced Polarization (PHIP) creates a hyperpolarized spin state by hydrogenation of a double or triple bond with parahydrogen1. A drawback of all the hyperpolarization techniques is the limited lifetime, since it is usually relaxing to the thermal equilibrium with the spin-lattice relaxation time T1. A longer lifetime can be achieved by storing the hyperpolarization as a singlet spin state. A requirement for the singlet state preservation is the reducing of the chemical shift (Cs) difference usually achieved by moving the sample to a low field or applying dedicated pulse sequences2. Recently, it was shown for the Cs-symmetric molecule dimethyl maleate that the hyperpolarized proton singlet state can be stored at 7 T for 4 min with no need of rf pulses3,4. To yield measurable magnetization the sample was transported to the resonance magnetic field at 0.1 T allowing for singlet-triplet conversion via level anti-crossing. Here, the singlet-triplet conversion is performed inside the observation field by an RF pulse sequence and combine with imaging.