Abstract
Hyperpolarization techniques can enormously enhance the NMR signal thus allowing the exploitation of hyperpolarized substrates for in-vivo MRI applications. The short lifetime of hyperpolarized spin order poses significant limitations in such applications. Spin order storage can be prolonged through the use of long-lived spin states. Additionally, the storage of spin polarization-either in the form of longitudinal or singlet order-can be prolonged in low viscosity solutions. Here, we report the use of low viscosity liquid-CO(2) solutions to store nuclear spin polarization in the form of longitudinal and singlet order for extended periods. Our results demonstrate that this storage time can be considerably sustained in liquid-CO(2) solutions in comparison to other low viscosity solvents, opening up the possibility of new, exciting storage experiments in the future.