orals 5th Asia-Pacific NMR Symposium 2013

Strategies for multidimensional NMR diffusiometry using inhomogeneous magnet systems (#101)

Marcel Nogueira d' Eurydice 1 , Petrik Galvosas 1
  1. Victoria University, Wellington, New Zealand

One sided NMR devices have become a very powerful tool in order to perform low field NMR diffusion and relaxation analysis. These analysis are very useful in the industry environment when evaluating the quality and quantity of Hydrogen based materials, besides distinguishing the content proportions of different phases in the samples. Several techniques have been developed over the last decade in order to take advantage of the characteristics of these devices, increasing their applicability to many different fields1-3.

In order to determine diffusion coefficients of fluids in different environments, this work uses a pulse sequence combining spin echo and CPMG experiments (SGSE-CPMG)4, where the first echo time is varied in each subsequent measurement to record a two-dimensional data set. Data processing is based on a two step inverse Laplace transformation. The first processes the set of CPMG decays to obtain a set of T2 distributions, which is used to correct for T2 relaxation during the first stage of the pulse sequence responsible for measuring the diffusion coefficients. Subsequently, the second determines the diffusion coefficient distribution using the T2 corrected data set in conjunction with a customized kernel, based on the results of a standard sample. As a result, this novel procedure enables the determination of DxT2 correlation maps even using the inhomogeneous magnetic field provided by the Mobile Lateral Explore (MOLE)5 magnet array without requiring pulsed field gradients.1 

This technique can be used to determine the proportional content of fluid mixtures as well as to explore diffusion of fluids in porous host systems using one sided NMR devices. The experiments were performed using the Kea2 spectrometer6 and the MOLE.

  1. B. Blümich, J. Perlo, and F. Casanova, Progress in Nuclear Magnetic Resonance Spectroscopy, 52 (2008) 197.
  2. E. Veliyulin, C. van der Zwaag, W. Burk, and U. Erikson Journal of Science of Food Agriculture. 85 (2005) 1299.
  3. I. G. Aursand, et al, Journal of Agriculture Food Chemistry. 57 1 (2009) 46.
  4. D. G. Rata, F. Casanova, J. Perlo, D. E. Demco, and B. Blümich, Journal of Magnetic Resonance, 180 (2006) 229.
  5. B. Manz, A. Coy, R. Dykstra, C. Eccles, M. Hunter, B. Parkinson & P. Callaghan, Journal of Magnetic Resonance, 183(1) (2006) 25
  6. http://www.magritek.com/