CONCLUSIONS
The reported proof-of-concept study demonstrated that combination
of HPLC-SPE with CapNMR is an attractive technique
for analysis of complex mixtures such as natural product extracts.A successful investigation of a plant extract using off-line combination
of automated HPLC-SPE with CapNMR was performed,
allowing structure determination of complex natural products
constituting less than 0.5% of the extract. The HPLC-SPE-CapNMR
technique combines the high mass sensitivity of the CapNMR
probe with the high loadability of standard HPLC columns and
the advantages of the SPE interface. HPLC-SPE-CapNMR hyphenation
is therefore regarded an important application of
CapNMR technology, supplementing its use in conjunction with
flow injection analysis and separations by capillary HPLC.