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Published April 2, 2008 | Accepted Version
Journal Article Open

PASADENA Hyperpolarization of Succinic Acid for MRI and NMR Spectroscopy


We use the PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) method to achieve ^(13)C polarization of ∼20% in seconds in 1-^(13)C-succinic-d_2 acid. The high-field ^(13)C multiplets are observed as a function of pH, and the line broadening of C1 is pronounced in the region of the pK values. The ^2J_(CH), ^3J_(CH), and ^3J_(HH) couplings needed for spin order transfer vary with pH and are best resolved at low pH leading to our use of pH ∼3 for both the molecular addition of parahydrogen to 1-^(13)C-fumaric acid-d_2 and the subsequent transfer of spin order from the nascent protons to C1 of the succinic acid product. The methods described here may generalize to hyperpolarization of other carboxylic acids. The C1 spin−lattice relaxation time at neutral pH and 4.7 T is measured as 27 s in H_2O and 56 s in D_2O. Together with known rates of succinate uptake in kidneys, this allows an estimate of the prospects for the molecular spectroscopy of metabolism.

Additional Information

© 2008 American Chemical Society. Received November 7, 2007. Publication Date (Web): March 12, 2008. We would like to thank Rudi Schulte Research Institute (RSRI), NIH 1R21 CA118509, NCI, James G. Boswell Fellowship, American Heart Association, American Brain Tumor Association, Beckman Institute Pilot Program (California Institute of Technology), Dr. William Opel for support of the PASADENA program at HMRI, and Dr. Keiko Kanamori (HMRI). We also thank Dr. Scott Ross for providing convenient access to a 14T Varian solution NMR spectrometer at Caltech. The PASADENA polarizer was provided under loan agreement between HMRI and GE Healthcare established by Dr. Klaes Golman, Ms. Marivi Mendizabal, and Dr. J.-H. Ardenkjaer-Larsen.

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Accepted Version - nihms96928.pdf


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