Insert the sample (ij).

Choose the solvent deuterium signal with the lock command

Tune and match the probehead (wobb or atma if required).

Optimize the shim procedure (read an optimized shim file with the rsh command or performs a gradshim if required).

Record a 1D ¹H WATERGATE spectrum and check o1, pl18, p27 and d19 for efficient solvent suppression.

Create a new dataset (new) and read the standard BRUKER parameter set (rpar) to record 2D ¹H-¹H TOCSY spectrum using WATERGATE solvent suppression with rpar DIPSI2GPPH19 all (the pulse program dipsi2gpph19 can be visualized in the PulsProg section or with the edcpul command).

It is generally recommended that TOCSY experiments be run without sample spinning. Update the corresponding pulses and power levels in the acquisition parameters according to the selected solvent/probehead parameters by executing the getprosol command (pulses and power levels must be correctly set by the edprosol command). If required, any acquisition parameter can be modified manually or in the AcquPars section.

Otherwhise, the required acquisition parameters can be displayed with the ased command. Modify the following parameters accordingly:

• o1 is set on the solvent resonance
• 2 sw is the spectral width in the F2 ¹H dimension
• 1 sw is the spectral width in the F1 ¹H dimension
• 2 td is the time domain in the F2 dimension (usually set to 1K-2K)
• 1 td is the number of experiments/increments to be recorded in the F1 dimension (usually set to 128w-256w)

d9 (about 60 ms by default) is the duration of the TOCSY mixing time which consists of a DIPSI-2 scheme:

pl10=power level for the TOCSY spin-lock (for calibration purposes see: 90º ¹H observe pulse calibration)

p6 = 90º ¹H pulse at pl10 power level (about 30-35 microseconds)

d20 and d21 are two z-filter delays usually set to 2 and 3 ms, respectively

Parameters defining the 3-9-19 WATERGATE pulse train are:

pl18 is the power level for these pulses (try the same power as pl1).

p27 is the 90 degree pulse at pl18.

2*d19 is the interpulse delay (start with d9=150 usec). Check for the first sidebands appearing to 1/(2*d).

Standard gradient parameters:

gpz1 (gpnam1=SINE.100) is set to 30%

gpz2 (gpnam2=SINE.100) is set to 30%

Gradient duration (p16)

Recovery delay (d16)

Set the number of scans as a function of the sample concentration (by default, ns 2 and ds 16).

Start acquisition by rga and zg (the expected experimental time is displayed with the expt command). Careful optimization of the solvent-dependent o1, d19 and p27 parameters can be performed by minimizing the FID in gs mode.

Process the recorded data with xfb. By default, SI2=SI1=1K and pure cosine squared sine window functions (WDW2=WDW1=QSINE) are applied to both dimensions (SSB2=SSB1=2) using MC2 (TPPI, States-TPPI ...) as defined in FnMODE.

Use the TOPSPIN plot editor (xwinplot)

It can be advisable to store all acquisition and processing parameters (with the command wpar) to be used later.

Both acquisition and processing steps can be performed using predefined automated AU programs. In this case, start data acquisition with the xaua command (the program executes the AU program defined in the acquisition parameters AUNM (au_getlcosy)) and the data can be automatically processed and plotted with the xaup command (the program executes the AU program defined in the processing parameter AUNMP (proc_2dhom).

This experiment can also by recorded in full automation mode using macros (edmac), BUTTON-NMR (buttonnmr) or ICON-NMR (iconnmr)

List of Related Experiments:

Phase-cycle TOCSY experiments
Gradient-enhanced TOCSY experiments
Gradient-enhanced TOCSY experiments in H₂O