Tayler Michael C D, Ward-Williams Jordan, Gladden Lynn F
Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK.
Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK.
J Magn Reson. 2018 Dec;297:1-8. doi: 10.1016/j.jmr.2018.09.014. Epub 2018 Oct 6.
NMR detection in the ultralow-field regime (below 10 μT) was used to measure the nuclear spin relaxation rates of liquids imbibed into silica pellets with mean pore diameters in the 10-50 nm range. Heptane, formic acid and acetic acid were studied and relaxation rate data were compared with a conventional field-cycling NMR technique. Detection of H-C spin coupling NMR signals at zero field (∼0.1 nT) allowed spectroscopic identification of molecules inside the porous material and unambiguous measurements of the chemistry-specific relaxation rates in liquid mixtures. In the case of molecules that contain H and C, spin-singlet state relaxation can provide additional information about the dynamics. Applications and future improvements to the methodology are discussed.
在超低场区域（低于10μT）利用核磁共振（NMR）检测来测量被吸入平均孔径在10 - 50nm范围内的二氧化硅颗粒中的液体的核自旋弛豫率。研究了庚烷、甲酸和乙酸，并将弛豫率数据与传统的场循环核磁共振技术进行了比较。在零场（约0.1nT）下检测H - C自旋耦合核磁共振信号，能够对多孔材料内部的分子进行光谱鉴定，并明确测量液体混合物中化学特异性弛豫率。对于含有H和C的分子，自旋单重态弛豫可以提供有关动力学的额外信息。文中还讨论了该方法的应用和未来改进。
