Lloyd L. Lumata1, Matthew E. Merritt1, Craig R. Malloy1, A. Dean Sherry1, 2, Johan van Tol3, Likai Song3, Zoltan Kovacs1
1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States; 2Department of Chemistry, University of Texas at Dallas, Richardson, TX, United States; 3National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, United States
We demonstrate the efficiency of stable free radicals BDPA, DPPH, and galvinoxyl as polarizing agents for dissolution dynamic nuclear polarization (DNP) NMR spectroscopy. Large NMR signal enhancements were achieved for biologically important labeled substrates such as [1-13C]pyruvic acid and [15N]choline. In addition, these hydrophobic free radicals can be easily filtered out in aqueous hyperpolarized liquids using a simple mechanical filtration process.