Proton observe and P31 CW decoupling
(This experiment is available on B500b and B400b. Performance of B500b is better than B400b)
(A) In ICONNMR way.
1. Set up a first experiment: P31CPD.
2. Set up a second experiment: PROTON. Set ns = 500 so that the experiment will keep the sample in the magnet and let you have time to look at the P31CPD spectrum.
Do not yet set up the third experiment: PROTONP31CWDEC.
3. Submit the first two experiments.
4. Start the run.
5. Wait until the P31CPD experiment finishes.
6. Display the P31CPD spectrum.
7. Get the ‘o1p’ value (the exact shift in ppm’s) of the interesting peaks.
8. Set up a third experiment, PROTONP31CWDEC, and set o2p = the value of ‘o1p’ obtained from the last step. (For B400b, set o2p = 1 PPM + the value of ‘o1p’ obtained from the last step. There is a software bug that the o1p reading from P31 experiment is not the exact o2p value, which gives the best decoupling effect).
9. Similarly set up more PROTONP31CWDEC experiments if there are more peaks of interest.
10. Submit these PROTONP31CWDEC experiments.
11. Read in the PROTON experiment currently running (click “FID”). Click “halt” (not “stop”!). The PROTON will be stopped and PROTONP31CWDEC will automatically start.
12. Compare PROTON and PROTONP31CWDEC spectra with multi-spectra display and see the difference. Only the H1 splitting due to the coupling of the irradiated P31 should collapse.
(B) In TOPSPIN way:
Make sure that the solvent is consistent in all the experiments. After lock and shimming finishes, run the following three experiments:
(1) Get P31 chemical shift for decoupling
Exp 10 1
‘rpar P31CPD all’ ‘getprosol’ ‘ii’ ‘rga’ ‘zg em ft’ phase.
Use “Set RF from cursor” to determine o1p of the P31 peaks.
Write down the O1p values for all the peaks interested.
(2) Get H1 spectrum with no P31 decoupling
Exp 20 1
‘rpar PROTON all’ ‘getprosol’ ‘ii’.
Change PulseProg ‘zg30’ to ‘zg’
‘rga’ ‘zg em ft’ phase.
write down the ‘rg’ value.
(3) Get H1 spectrum with P31 CW decoupling
Exp 30 1
‘rpar PROTONP31CWDec all’, ‘getprosol’, ‘ii’.
Set o2p = the value of ‘o1p’ obtained from the step (1). (For B400b, set o2p = 1 PPM + the value of ‘o1p’ obtained from the step (1). There is a software bug that the o1p reading from P31 experiment is not the exact o2p value, which gives the best decoupling effect).
Set ‘rg’ = the value obtained in step (2).
‘zg em ft’ phase.
Compare the H1 spectrum to one without P31 decoupling (step 2).
Only the H1 splitting due to the coupling of the irradiated P31 should collapse.