title: Diffusion exchange NMR spectroscopy in inhomogeneous magnetic fields.
abstract: Two-dimensional diffusion exchange experiments in the presence of a strong, static magnetic field gradient are presented. The experiments are performed in the stray field of a single sided NMR sensor with a proton Larmor frequency of 11.7 MHz. As a consequence of the strong and static magnetic field gradient the magnetization has contributions from different coherence pathways. In order to select the desired coherence pathways, a suitable phase cycling scheme is introduced. The pulse sequence is applied to study diffusion as well as the molecular exchange properties of organic solvents embedded in a mesoporous matrix consisting of a sieve of zeolites with a pore size of 0.8 nm and grain size of 2 μm. This pulse sequence extends the possibilities of the study of transport properties in porous media, with satisfying sensitivity in measurement times of a few hours, in a new generation of relatively inexpensive low-field NMR mobile devices.
authors.affiliation: Fachgebiet Technische Physik II/Polymerphysik, Institute of Physics, Technische Universität Ilmenau, PO Box 100 565, 98684 Ilmenau, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Neudert
authors.forename: Siegfried
authors.initials: S
authors.lastname: Stapf
authors.forename: Carlos
authors.initials: C
authors.lastname: Mattea
mesh_terms: D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D004058:Diffusion; D004574:Electromagnetic Fields; D005240:Feasibility Studies; D006586:Hexanes / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D016062:Porosity; D012997:Solvents; D017641:Zeolites
chemical_list: D006586:Hexanes; D012997:Solvents; D017641:Zeolites; C026385:n-hexane