High Resolution Hyperpolarized J-spectra with Parahydrogen Discrimination

I. PRINA; L. BULJUBASICH; R.H. ACOSTA

Egmond aan zee

Congreso; Hyperpolarized Magnetic Resonance; 2015

Hyperpolarization by parahydrogen (PHIP) has become a powerful tool not only to overcome the low intrinsic sensitivity of Nuclear Magnetic Resonance (NMR) but also as a probe for catalytic reactions,development of contrast agents for magnetic resonance imaging (MRI) or in analytic chemistry. In complex systems, the enhanced antiphase signals steaming from parahydrogen in a PASADENA (Parahydrogenand Synthesis Allow Dramatically enhanced Nuclear Alignment)1 experiment can be partially cancelled by the presence of magnetic fields inhomogeneities or due to the presence of large thermally polarizedsignals.In this work we present a simple solution to overcome these problems by application of a modified CMPG sequence using the well-known method of J-spectroscopy2. The method relies on the acquisition of Jspectrain PHIP, which differs from J-spectra for thermally polarized species due to different evolution in the time domain during the application of a Carr-Purcell-Meiboom-Gill (CPMG) sequence. Namely, signalsdue to PHIP present an odd-even effect with the 180º refocusing pulses which produces a shift in half of the spectral width upon a Fast Fourier Transformation. Experimental results are show to demonstrate theversatility of this technique in different conditions, for instance, highly diluted samples3 or thermally polarized background4 at 7 Tesla or in the strong coupling regime with inhomogeneous magnetic fields (0.5Tesla)5.