第6回 東北イオニクス研究会
第6回東北イオニクス研究会
Willium S. Price先生(オーストラリア西シドニー大学)による特別講演
題目：
『NMR Diffusometry – Principles and Applications』
講演要旨：
Translational diffusion (‘diffusion’) by random thermal motion is the most fundamental form of molecular transport. Diffusion is a natural probe of solution interactions, including molecular association (e.g., protein self-association), since it is directly linked to the size and shape of the diffusing species. Further, if the diffusion occurs within a porous medium (e.g., biological cell, vesicle, rock pore …) and the timescale of the diffusion measurement, D, is such that the diffusing molecules have time to interact with any boundaries, then the measurement will provide information on the size and shape of the boundaries.
NMR, in the guise of the Pulsed Gradient Spin-Echo (PGSE) NMR technique (also known as NMR diffusometry, DOSY or q-space imaging) provides a convenient and powerful means of measuring diffusion. Importantly, the technique is non-invasive, accurate, not limited by high solute concentrations and, as it still retains NMR spectral characteristics, offers the possibility of measuring the diffusing of multiple species at the same time.1,2 It has two other properties which greatly add to its power: it allows diffusion to be measured over a specified D (on the order of milliseconds) in any chosen direction – consequently, it is sensitive to diffusive – and hence microstructural-anisotropy.
Most contemporary NMR spectrometers have at least some diffusion measuring capability and NMR spectrometers that can perform conventional (‘k-space’) magnetic resonance imaging afford the possibility of performing localised diffusion measurements (‘diffusion MRI’) which is invaluable in studying heterogeneous materials - which includes clinical applications. With specialised diffusion NMR hardware, it is possible to measure diffusion coefficients ranging from ~10-6 m2s-1 (‘gas phase’) to ~10-15 m2s-1 (large polymers).
This talk will consider the basis of the PGSE NMR technique, and then some recent developments and applications from my group including resolving isomers and supercooled liquids,3,4 and new experiments and analysis for probing porous media.5-7
1. W. S. Price, NMR Studies of Translational Motion: Principles and Applications, 1st (Cambridge: Cambridge University Press, 2009).
2. P. T. Callaghan, Translational Dynamics & Magnetic Resonance, 1st (Oxford: Oxford University Press, 2011).
3. D. J. Codling, G. Zheng, T. Stait-Gardner, S. Yang, M. Nilsson, and W. S. Price, Diffusion studies of dihydroxybenzene isomers in water-alcohol systems. J. Phys. Chem. B 117 (2013), 2734-41.
4. P. Garbacz and W. S. Price, 1H NMR Diffusion Studies of Water Self-diffusion in Supercooled Aqueous Sodium Chloride Solutions. J. Phys. Chem. A 118 (2014), 3307-12.
5. N. N. Yadav, A. M. Torres, and W. S. Price, NMR q-space imaging of macroscopic pores using singlet spin states. J. Magn. Reson. 204 (2010), 346-48.
6. A. M. Torres, B. Ghadirian, and W. S. Price, Diffusion-diffraction using singlet spin states and various NMR coherences in a J-coupled AX spin system. RSC Advances 2 (2012), 3352-60.
7. B. Ghadirian, A. M. Torres, N. N. Yadav, and W. S. Price, Restricted diffusion in annular geometrical pores. J. Chem. Phys. 138 (2013), 094202-1-094202-11.
日時：2016年4月5日(火) 13:30~15:00
開催場所：片平キャンパス 多元研事務部棟2F 小会議室
http://www2.tagen.tohoku.ac.jp/information/campus.html