Korchak, Sergey, Lukas Kaltschnee, Riza Dervisoglu, Loren Andreas, Christian Griesinger, and Stefan Glöggler. “Spontaneous Enhancement of Magnetic Resonance Signals Using a RASER.” Angewandte Chemie 133, no. 38 (September 13, 2021): 21152–58.
https://doi.org/10.1002/ange.202108306.
Nuclear magnetic resonance is usually drastically limited by its intrinsically low sensitivity: Only a few spins contribute to the overall signal. To overcome this limitation, hyperpolarization methods were developed that increase signals several times beyond the normal/thermally polarized signals. The ideal case would be a universal approach that can signal enhance the complete sample of interest in solution to increase detection sensitivity. Here, we introduce the combination of para-hydrogen enhanced magnetic resonance with the phenomenon of the RASER: Large signals of para-hydrogen enhanced molecules interact with the magnetic resonance coil in a way that the signal is spontaneously converted into an in-phase signal. These molecules directly interact with other compounds via dipolar couplings and enhance their signal. We demonstrate that this is not only possible for solvent molecules but also for an amino acid.