Kinetics on Bruker TOPSPIN
(1H and 31P Kinetic are available on b400b, b500 and b500b, F19 Kinetic
is only available on b400b)
I. Data Acquisition:
General Procedure for 1H (or 31P, 19F) data collection (performed
manually in TOPSPIN, not in IconNMR):
1. Perform normal determination of PW90, T1, etc. prior to running
experiment.
2. Create new filename, starting in EXPNO 1.
3. ‘rpar PROTON (or ‘P31CPD’ for 31P, F19CPD for 19F), copy all,
‘getprosol’, then ii. Check p1 (a few us) and pl1 (~ odB).
4.Type ‘solvent’ and set correct solvent. Enter desired values for p1
(pw90), sw, o1, d1, ns, etc.
5. If applicable, enter edte menu and set desired temperature.
6. Quickly acquire and phase an initial spectrum (rga, zg) spectrum,
checking the SW and O1 setting (correct phasing here is useful for
automated processing later).
7. Using “AcquProc” menu change the pulse program from ‘zg30’ to
‘zg30_multi’ and set d5 to desired time interval between successive
spectra. (For P31{1H}, select ‘zgpg30_multiP31’, and for F19{1H},
select zg90_multiF19).
8. type ‘multizg’. You will be asked for the total number of experiments
to acquire (default 10). Up to 999 experiments may be collected at
intervals of d5, although 100 or less is recommended to allow for
practical data processing.
9. upon completion of experiment, you will see multizg finished
window.
10. Reset edte to room temperature, and continue to section II for data
processing.
II. Data Processing:
1. Return to the first spectrum, expno 1 (re 1).
2. For automatic Fourier transform/autophase/baseline-correction of the
spectra, type ‘multiefp’ starting in expno 1.
3. To perform automatic integration, return to experiment 1 (re 1) and
set integral regions. Use of an internal standard is strongly
recommended, as definition of a reference integral is required. Click
“Terminate integrate and save region” or “save region” as “intrng’ to
exit from “interactive Integrate”.
4. type ‘wmisc’, click on intrng, and save as new filename, e.g.
‘integrals’
5. Run command ‘multiinteg’ in main window.
6. Choose 0 for expno, the default. Enter 1 for first experiment
number, followed by the total number of data sets acquired.
7. Enter integral region file name, e.g., ‘integrals’ (filename defined
in step 4). Automatic integration is performed. The result is stored
in a file called dataset-name_int.txt, which will be deposited in the
pdata directory of your first expno, procno = 1. The output is written
in a format suitable for import in excel or similar desktop publishing
programs.
8. Calculating time points between collected FIDs for concentration vs.
time plots: There is significant error if the time intervals are
calculated by NS(AQ+D1)+D5 due to Input/Output delay in the
computer/software. It is therefore necessary to compute the time
interval using the file acqus in each experiment numbers directory.
Open this file with a text editor, and read the timestamp near the top
to get hh:mm:sec information for when the file fid was created.
Average the interval (in seconds) for the first 10 or so spectra. This
will be the time interval for use in a spreadsheet.
The above example was for 1H Kinetic data acquisition. The same method
applies for 31P, 31P{1H}, 19F, and 19F{1H}, or any other nucleus
amenable to kinetic investigation.
Tips:
If you took an initial spectrum and phased it prior to running
multizg, then you can use the multiefp command to quickly transform the
data.
For VT runs, the initial spectrum is best acquired quickly (ns = 1 or
2) and phased at temperature before running multizg, since the phasing
will be slightly off from the ambient temp spectrum.
Troubleshooting:
Ensure correct probehead definition, especially for 31P or 19F
kinetics. If you dont see an fid, enter eda menu and click PROSOL
button (below solvent description) to TRUE to make sure correct
probehead is listed (5mm_QNP_H-F-P-C). Use edhead to fix probe
description, click on define current, then the probe, then save.
If you acquired an initial spectrum in experiment 1 to check sweep
width and O1, and multizg gives a warning to overwrite the current
data, you will need to disable the zgsafety function. Enter setres
menu, and make sure zgsafety=off (near top right side).