Continuous ¹H and ¹³C Signal Enhancement in NMR Spectroscopy and MRI Using Parahydrogen and Hollow‐Fiber Membranes

Abstract

Parawasserstoff‐induzierte Polarisation ermöglicht die kontinuierliche Erzeugung hyperpolarisierter Moleküle. Die konstante Verstärkung von 1H‐ und 13C‐NMR‐Signalen mithilfe einer kontinuierlichen Parawasserstoff‐Zufuhr durch Hohlfasermembranen wird vorgestellt (links im Bild). So gelingt die Akquisition zweidimensionaler NMR‐Signale, für die Mehrfachakquisitionen mit konstanter Anfangspolarisation notwendig sind.

Irreversible Catalyst Activation Enables Hyperpolarization and Water Solubility for NMR Signal Amplification by Reversible Exchange

“… 19 , 43 Nevertheless, the SABRE enhancements in water can be potentially increased through the use of higher p -H 2 partial pressures (e.g., ≥10 bar) frequently used in conventional PHIP. 10 Furthermore, additional gains of aqueous SABRE enhancements may be realized through better mixing of catalyst/substrate solution with p -H 2 , which has already been shown through the use of solution spray injection in p -H 2 atmosphere, 45 , 46 or hollow fiber membranes, 23 , 47 and the optimization of other conditions (e.g., temperature and magnetic field). 18 , i …”

Heterogeneous Solution NMR Signal Amplification by Reversible Exchange

“…Following the progress with conventional PHIP [8] and Overhauser DNP, [9] we report herein the first observation of SABRE enhancement of NMR signals in solution using a heterogeneous catalyst. The novel HET-SABRE catalyst is prepared by immobilizing an iridium-based organometallic catalyst onto micropolymer beads.…”

Use of Labile Precursors for the Generation of Hyperpolarized Molecules from Hydrogenation with Parahydrogen and Aqueous‐Phase Extraction

“…To avoid the step associated to the removal of the organic solvent, the use of water‐soluble catalysts has been proposed. Recently, an important contribution has been given by using hollow fiber membranes that allow a continuous delivery of hydrogen gas to be obtained in aqueous solution at 3 bar 15. However, to obtain a certain amount of polarized molecules within a few seconds that can be used for imaging purposes, high pressures (10 bar) are usually necessary while the amount of hyperpolarized product is often rather small, especially with biocompatible substrates.…”