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HMQC/HSQC of codeine

HMQC/HSQC of codeine

HMQC / HSQC 1-bond CH correlation

Comparison of phase-sensitive HSQC using echo-antiecho  (JEOL experiment name: hsqc_pfg_s_phase_pn.exp ) and magnitude mode HMQC (JEOL experiment name:  hmqc_irr_pfg_s.exp )   (see notes about HMQC processing)

Comparison of experiments run on 4 mg codeine sample using

2 scans
128 t1 increments (note that because hsqc is phase sensitive, it takes twice as long to acquire the same number of t1 increments)
512 complex points in direct dimension

signal-to-noise ratio (S/N) measured at N-Me for HMQC (with phase of sine squared window fcn of 45) was twice that of HSQC, but S/N of the smaller peaks is comparable for both spectra.

HMQC:  (total acquisition time ~9 min)

 

HSQC – note that peaks are sharper, so overlapping peaks are less of a problem.   (total acquisition time ~18 min)

Processing:

HMQC:

sine squared window function in both dimensions with 45 degree phase shift
2x zero-fill in the indirect dimension
magnitude calculation (no phasing is required)
final data size 512 x 512

HSQC:

this is an echo-antiecho experiment;  see details
sine squared window function in both dimensions with 90 degree phase shift
2x zero-fill in the indirect dimension
final data size 512 x 512

See also:  Explanation of the HMQC experiment, processing HMQC data, HMBC


Last updated:  01/22/2003