Details

Autor(en) / Beteiligte

• Akpa, Belinda S
• Holland, Daniel J
• Sederman, Andrew J
• Johns, Michael L
• Gladden, Lynn F

Titel

Enhanced (13)C PFG NMR for the study of hydrodynamic dispersion in porous media

Ist Teil von

• Journal of magnetic resonance (1997), 2007-05, Vol.186 (1), p.160-165

Ort / Verlag

United States

Erscheinungsjahr

2007

Quelle

MEDLINE

Beschreibungen/Notizen

• PFG NMR methods are frequently used as a means of probing both coherent and incoherent molecular motions of fluids contained within heterogeneous porous media. The time scale over which molecular displacements can be probed in a conventional PFG NMR experiment is limited by the relaxation characteristics of (1)H - the nucleus that is typically observed. In multiphase systems, due to its sensitivity to susceptibility gradients and interactions with surfaces,(1)H signal is frequently characterized by rapid T(1) and T(2) relaxation. In this work, a heteronuclear approach to PFG NMR is demonstrated which allows the study of molecular displacement over extended time scales (and, consequently, length scales) by exploiting the longer relaxation time of (13)C. The method presented employs the DEPT technique of polarization transfer in order to enhance both the sensitivity and efficiency of (13)C detection. This hybrid coherence transfer PFG technique has been used to acquire displacement propagators for flow through a bead pack with an observation time of up to 35 s.