Department of Chemistry, University of Miami, Coral Gables, FL 33146, USA.
Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL 33124, USA.
Phys Chem Chem Phys. 2021 Sep 15;23(35):19244-19254. doi: 10.1039/d1cp02077c.
In this work, the second-order kinetics of molecules exchanging between chemically distinct microenvironments, such as those found in nanoemulsions, is studied using nuclear magnetic resonance (NMR). A unique aspect of NMR exchange studies in nanoemulsions is that the difference in molecular resonance frequencies between the two phases, which determines whether the exchange is fast, intermediate, or slow on the NMR timescale, can depend upon the emulsion droplet composition, which is also determined by the kinetic exchange constants themselves. Within the fast-exchange regime, changes in resonance frequencies and line widths with dilution were used to extract the exchange rate constants from the NMR spectra in a manner analogous to determining the kinetic parameters in NMR ligand binding experiments. As a demonstration, the kinetic exchange parameters of isoflurane release from an emulsification of isoflurane and perflurotributylamine (FC43) were determined using NMR dilution and diffusion studies.
在这项工作中，使用核磁共振（NMR）研究了分子在化学上不同的微环境（如纳米乳液中存在的微环境）之间交换的二级动力学。NMR 交换研究在纳米乳液中的一个独特方面是，两个相之间的分子共振频率的差异决定了交换在 NMR 时间尺度上是快速、中间还是缓慢，而这种差异取决于乳液液滴的组成，而乳液液滴的组成又取决于动力学交换常数本身。在快速交换区域内，通过稀释来改变共振频率和线宽，以便从 NMR 光谱中提取交换速率常数，这种方法类似于在 NMR 配体结合实验中确定动力学参数。作为一个演示，使用 NMR 稀释和扩散研究确定了异氟烷从异氟烷和全氟三丁胺（FC43）的乳化液中的释放的动力学交换参数。
