Improved SABRE hyperpolarisation using pulse sequences to reduce effective coupling

TL;DR

This paper introduces pulse sequences that intentionally slow down polarisation transfer in SABRE hyperpolarisation, leading to improved polarisation yield especially in systems with higher magnetic inequivalence and lower exchange rates.

Contribution

It demonstrates that slowing polarisation transfer with specific NMR sequences can enhance SABRE hyperpolarisation efficiency, a novel approach compared to traditional fast transfer methods.

Findings

Pulse sequences can improve SABRE polarisation yield.

Higher efficiency in systems with higher magnetic inequivalence.

Effective in systems with lower chemical exchange rates.

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 on-going chemical exchange process. Typically, polarisation transfer is achieved as fast as possible. In this study we employ NMR sequences that on contrary slow down the polarisation transfer and yet demonstrate improved performance. Simulations confirm that such methods can lead to high polarisation yield in SABRE system that exhibit higher magnetic inequivalence and lower chemical exchange rate.