IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Separation of Hyperpolarized from thermal signals in PASADENA.
Autor/es:
I. PRINA; L. BULJUBASICH; M. B. FRANZONI; R. H. ACOSTA
Reunión:
Conferencia; 5th International DNP Sym- posium and COST action EUROHyperPOL final meeting; 2015
Resumen:
Hyperpolarization by parahydrogen (PHIP) [1] 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 (Parahydrogen and Synthesis Allow Dramatically enhanced Nuclear Alignment) [2] experiment can be partially cancelled by the presence of magnetic fields inhomogeneities or due to the presence of large thermally polarized signals.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-spectroscopy [3]. The method relies on the acquisition of J-spectra in 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 [4]. Namely, signals due 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 the versatility of this technique in different conditions, for instance, highly diluted samples [5] or thermally polarized background [6] at 7 Tesla or in the strong coupling regime with inhomogeneous magnetic fields (0.5 Tesla) [7].