Parahydrogen-Induced Polarization (PHIP) is a potent technique for generating target molecules with high nuclear spin polarization. The PHIP process involves a chemical reaction between parahydrogen and a target molecule, followed by the transformation of nuclear singlet spin order into magnetization of a designated nucleus through magnetic field manipulations. Although the singlet-to-magnetization polarization transfer process works effectively at moderate concentrations, it is observed to become much less efficient at high molar polarization, defined as the product of polarization and concentration. This strong dependence on the molar polarization is attributed to interference from the field produced by the sample's magnetization during polarization transfer, which leads to complex dynamics and can severely impact the scalability of the technique. We address this challenge with a pulse sequence that negates the influence of the distant dipolar field, while simultaneously achieving singlet-to-magnetization polarization transfer to the desired target spins, free from restrictions on the molar polarization.
@article{arxiv.2401.07243,
title = {Robust Parahydrogen-Induced Polarization at High Concentrations},
author = {Laurynas Dagys and Martin C. Korzeczek and Anna J. Parker and James Eills and John W. Blanchard and Christian Bengs and Malcolm H. Levitt and Stephan Knecht and Ilai Schwartz and M. B. Plenio},
journal= {arXiv preprint arXiv:2401.07243},
year = {2024}
}