Improved SABRE hyperpolarisation using pulse sequences to reduce effective coupling

Abstract

Hyperpolarisation using signal amplification by reversible exchange (SABRE) is a convenient method for high repeatability studies. The core of this technique is polarisation transfer to the target substrate during an ongoing chemical exchange process. Typically, polarisation transfer is achieved as fast as possible. In this study, we employ NMR sequences that on the contrary slow down the polarisation transfer and yet demonstrate improved performance. Simulations confirm that such methods can lead to high polarisation yield in SABRE systems where hydride protons exhibit stronger magnetic inequivalence and substrates exchange with a lower rate.