Collecting CEST Data

Collecting CEST Data

1. Open TopSpin >= 3.2.X
2. Edit temperature
   1. “edte”
3. Create a dataset and collect a NHSQC to check resolution and NS
4. Type “edpy”, select n15cest_gb.py.
5. Click “execute” and hit “ok”.
6. Carrier Positions

• 1H water pos. (O1) = 3290.987 Hz (this can be changed)
• 15N carrier pos = 118 ppm
• 13C carrier pos = 118ppm (pseudo dimension)

1. Click “Ok”
2. Calibrated pulse values:

• 1H hard pulse = 10.25us @ -7.558748 dB (can be changed)
• 15N hard pulse = 35us @ -19.0309 dB
• 13C hard pulse = 12us @ -18.60338 dB

1. Click “Ok”
2. Values related to the weak B1 irradiation:

• 15N weak B1 field = 25 Hz (can be changed)
• Upfield irradiation offset limit = 100 ppm (can be changed)
• Downfield irradiation offset limit = 140 ppm (can be changed)
• Offset step size = 25 Hz (can be changed)

1. Click “Ok”
2. The experiment dataset will now be created. F1 is the pseudo dimension with the TD being the # of offsets that will be collected. The delays for these offsets can be found it FQLIST/FQ3LIST/n15cest_offset_std. This list name is overwritten each time a new CEST experiment is created so it is best to rename.
3. Edit F3 and F2 TDs.
4. DS must be >= 32.
5. NS must be >= 2.
6. Edit routing.
7. Click “Edit” for CPDPRG, change 90x240y90x to 90x_240y_90x
8. Make sure P50, P51, and P52 are all 500us
9. Calculate receiver gain
   1. “rga”
10. Edit D2 (t1 time)
11. Must also edit D3 so that D3 > D2.
12. Check ZGOPTNS
13. “zg”
14. The planes can be checked with “XFB”
    1. “xfb s23” plane 1
15. Also, collecting the first plane is advisable.