Zhang, Y., et al., Singlet lifetime measurements in an all-proton chemically equivalent spin system by hyperpolarization and weak spin lock transfers. Phys. Chem. Chem. Phys., 2015. 17(37): p. 24370-24375.
http://dx.doi.org/10.1039/C5CP03716F
Hyperpolarized singlet states provide the opportunity for polarization storage over periods significantly longer than T1. Here, we show how the singlet state in a chemically equivalent proton spin system can be revealed by a weak power spin-lock. This procedure allowed the measurement of the lifetimes of the singlet state in protic solvents. The contributions of different intra- and intermolecular relaxation mechanisms to singlet lifetimes are investigated with this procedure.