High-Resolution hyperpolarized J -spectra with parahydrogen discrimination

Abstract

Parahydrogen-induced polarization (PHIP) has become a powerful tool not only to overcome the low intrinsic sensitivity of nuclear magnetic resonance (NMR) but also as a probe for catalytic reactions, as a contrast agent in magnetic resonance imaging (MRI), or in analytic chemistry. In complex systems, the antiphase signals coming from parahydrogen in a PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) experiment can be partially canceled by the presence of large thermally polarized signals. In the present work, we present a simple method to separate the thermal and hyperpolrized contributions by taking advantage of their very different evolution during a modified CPMG sequence. The separation is obtained in combination with a property of the fast Fourier transform algorithm (FFT). The technique is experimentally demonstrated for a mixture of hyperpolarized 1-hexene and a large amount of CH2Cl2.