A continuous-flow, high-throughput, high-pressure parahydrogen converter for hyperpolarization in a clinical setting

J.-B. Hövener, S. Bär, J. Leupold, K. Jenne, D. Leibfritz, J. Hennig, S.B. Duckett, D. Von Elverfeldt

Research output: Contribution to journalArticlepeer-review

Abstract

Pure parahydrogen (pH) is the prerequisite for optimal pH-based hyperpolarization experiments, promising approaches to access the hidden orders of magnitude of MR signals. pH production on-site in medical research centers is vital for the proliferation of these technologies in the life sciences. However, previously suggested designs do not meet our requirements for safety or production performance (flow rate, pressure or enrichment). In this article, we present the safety concept, design and installation of a pH converter, operated in a clinical setting. The apparatus produces a continuous flow of four standard liters per minute of ≈98% enriched pH at a pressure maximum of 50bar. The entire production cycle, including cleaning and cooling to 25K, takes less than 5h, only ≈45 min of which are required for actual pH conversion. A fast and simple quantification procedure is described. The lifetimes of pH in a glass vial and aluminum storage cylinder are measured to be T(glass vial)=822±29min and T(Al cylinder)=129±36days, thus providing sufficiently long storage intervals and allowing the application of pH on demand. A dependence of line width on pH enrichment is observed. As examples, H hyperpolarization of pyridine and C hyperpolarization of hydroxyethylpropionate are presented.
Original languageEnglish
Pages (from-to)124-131
JournalNMR in Biomedicine
Volume26
Issue number2
DOIs
Publication statusPublished - 1 Feb 2013

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