  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.
