We have worked with both the MicroCryoProbee
and CapNMRe, which are currently the two leading
NMR technologies with the sensitivity enhancements
that truly offer structure elucidation on microgram
amounts of sample for natural products. Like most advanced
technologies in scientific disciplines with numerous
applications, each technology has their advantages
and disadvantages. The MicroCryoProbee is better suited
for samples with limited solubilities requiring 100 lL
of solvent and performing 13C and DEPT experiments
with approximately 200 or more micrograms of material.
The CapNMRe has a higher filling factor resulting
in fewer non-deuterated artifacts during acquisition, so
it obtains better spectra when acquiring 1H and COSY
NMR spectra on approximately 5 to 10 lg of material.
In our experience the MicroCryoProbee and Cap-
NMRe are equivalent when performing HSQC and
HMBC experiments on 30 and 70 lg, respectively. The
gain in sensitivity using the capillary-scale NMR probe