The use of HPLC-DAD-SPE-NMR technique was demonstrated
to be a major advance for the rapid structural elucidation of a
range of complex constituents of a plant extract. Complete
structure elucidation and assignment of 1H and 13C NMR signals
of complex natural products was shown to be possible from
analytical-scale HPLC separation of essentially crude extracts.
Although HPLC-SPE-NMR is significantly less sensitive than
HPLC-MS, it is superior in its ability to provide detailed structural
information, including the possibility of distinguishing between
positional isomers and stereoisomers. It is believed that the HPLCDAD-
SPE-NMR technique, which is inexpensive and rectifies most
of the disadvantages of classical HPLC-NMR methods, will be an
increasingly important analytical platform in natural product
research and in other areas where rapid structural analysis of
complex constituents of mixtures is required.