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 conventional ¹H spectrum with presaturation. Note the o1p and SW values to optimize spectral widths in the corresponding 2D experiment.

Create a new dataset (new) and read the standard BRUKER parameter set (rpar) to record a 2D phase-sensitive ¹H-¹H COSY-45 spectrum using presaturation with rpar COSYDQFPHSW all and change the pulse program to cosydfphpr that can be visualized in the PulsProg section or with the edcpul command).

It is generally recommended that COSY-DQF 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:

• o1p is the center of the spectrum
• 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)

Set o1p on the solvent resonance and check for the power level (try pl9=55-60dB) and the duration (d1=1.5-2s) for an efficient solvent presaturation.

Finally, set the number of scans as a function of the sample concentration (by default, ns 16 and ds 4).

Start acquisition by rga and zg (the expected experimental time is displayed with the expt command). Careful optimization of the solvent-dependent o1, d1 and pl9 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 COSY experiments
Gradient-enhanced COSY experiments