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ANALYTICAL CURRENTS Boosting NMR’s S/N A new NMR approach is yielding amazing increases—as much as 40,000—in the S/N of low-abundance nuclei, such as 13C, over conventional methods. Jan Ardenkjær-Larsen and colleagues with Amersham Health Research and Development AB (Sweden) combine dynamic nuclear polarization (DNP) in the solid state with fast dissolution into solution to overcome NMR’s notoriously poor sensitivity. In this proof-of-principle study, the Amersham scientists easily measured natural abundance 13C and 15N spectra of urea following hyperpolarization of the nuclear spins at liquid helium temperatures. The trick was to quickly dissolve the analyte into solution to minimize the loss of polarization. In this case, the transfers were complete in
