Department of Analytical Chemistry, Faculty of Natural Sciences, Leibniz University Hanover, Hanover, Germany.
Anal Chem. 2011 Feb 15;83(4):1328-35. doi: 10.1021/ac102389b. Epub 2011 Jan 14.
High-efficiency separation techniques, such as capillary electrophoresis (CE), coupled to a nondestructive nuclear magnetic resonance (NMR) spectrometer offer the ability to separate, chemically identify, and provide structural information on analytes in small sample volumes. Previous CE-NMR coupled systems utilized laboratory-scale NMR magnets and spectrometers, which require very long separation capillaries. New technological developments in electronics have reduced the size of the NMR system, and small 1-2 T permanent magnets provide the possibilities of a truly portable NMR. The microcoils used in portable and laboratory-scale NMR may offer the advantage of improved mass sensitivity because the limit of detection (LOD) is proportional to the coil diameter. In this work, CE is coupled with a portable, briefcase-sized NMR system that incorporates a microcoil probe and a 1.8 T permanent magnet to measure (19)F NMR spectra. Separations of fluorinated molecules are demonstrated with stopped- and continuous-flow NMR detection. The results demonstrate that coupling CE to a portable NMR instrument is feasible and can provide a low-cost method to obtain structural information on microliter samples. An LOD of 31.8 nmol for perfluorotributylamine with a resolution of 4 ppm has been achieved with this system.
高效分离技术，如毛细管电泳（CE）与非破坏性核磁共振（NMR）光谱仪相结合，能够分离、化学识别并提供小样本量分析物的结构信息。以前的 CE-NMR 耦合系统使用实验室规模的 NMR 磁铁和光谱仪，这需要非常长的分离毛细管。电子技术的新发展缩小了 NMR 系统的尺寸，而 1-2T 的小型永磁体则提供了真正便携式 NMR 的可能性。便携式和实验室规模 NMR 中使用的微线圈可能具有提高质量灵敏度的优势，因为检测限（LOD）与线圈直径成正比。在这项工作中，CE 与便携式公文包大小的 NMR 系统耦合，该系统结合了微线圈探头和 1.8T 永磁体，用于测量（19）F NMR 光谱。用停流和连续流 NMR 检测来演示氟化分子的分离。结果表明，将 CE 与便携式 NMR 仪器相结合是可行的，并可以提供一种低成本的方法来获得微升样品的结构信息。该系统实现了对全氟三丁胺的 31.8nmol 的检测限（LOD）和 4ppm 的分辨率。
