ABSTRACT
The coupling of chromatographic techniques to nuclear magnetic resonance (NMR) detection has become increasingly important over the last few decades. In particular, the hyphenation of high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) to NMR have been at the forefront of these developments. For unknown or complex substances, it is not uncommon to have overlapping signals in the NMR spectrum complicating the structure elucidation of unknown analytes. For this reason, the experimental protocol typically requires that sample components undergo a separation or extraction step prior to NMR using HPLC, supercritical fluid chromatography (SFC), or CE. While it is possible to collect fractions of interest and measure the NMR spectrum offline, coupling of the separation directly with online NMR detection is a practical way to eliminate unnecessary transfer steps and minimize sample loss or degradation. This review describes recent advances in hyphenation of chromatographic techniques with NMR detection, presents the advantages and limitations of the various approaches, and summarizes selected applications of these methods. The recent review by Jayawickrama and Sweedler on the hyphenation of capillary separations with NMR also touches on many of the topics discussed herein [1].
