2D Experiments Common Setup

2D Experiment Setup Steps

The following applies to all ¹H-detected, 2D experiment setup unless otherwise instructed.

All 2D experiments are recommended to be conducted on NMR600.
The following hardware setting is default and is necessary for all 2D experiments. No user action is needed.
Sample spinning must be turned OFF
Temperature should be regulated (default at 25C).
Pulsed field gradients (PFG) should be activated.

Step 1: Load sample, lock and shim as usual.

Step 2: Set 1H spectral width in direct detect dimension

Collect a simple 1H spectrum (nt=1 is fine) or load a recently collected 1H spectrum with the sample.
Process data and display full spectrum (wft aph f full). Use the box cursor (two cursor lines, see image below) to enclose the entire signal region. Leave 5-10% baseline region to the left and right sides of the signal region. Note: the entire signal region with significant peaks must be enclosed between the two cursors, not just the region you are interested in.

Enter movesw to set the new spectral window to the current cursor-enclosed region.
Enter nt=1 go to recollect a quick spectrum with new window. Enter wft aph f full to process it. Enter setref to reference it by solvent/lock signal.

Step 3: Use the selected 1H window size and set up 2D experiment

Under the current experiment (from Step 2), simply enter setexp('exp_name') to set up the 2D experiment with current solvent and 1H spectral window. In most cases, use default values for all other parameters. The exp_name should be replaced with an appropriate name, i.e. ghsqc, ghmbc, ..etc.
For multiple 2D experiments setup:
Click Process→Text Output. Enter explib to show current experiment library list. Note current experiment number (exp1 is assumed here) shown in the upper left corner of the spectrum window. This is the 1D 1H experiment with the adjusted window.
If exp2 exists, enter jexp2. If not, enter cexp(2) jexp2, or click File→New Workspace and note the new experiment number displayed.
Enter mf(1,2) to move FID from exp1 to exp2 (change exp# accordingly). Enter wft f full to display data.
Under the new experiment, enter setexp('exp_name')
The above procedure can be repeatedly so that all 2D exps are set up for the sample. Write down which exp# is which experiment.
Check specific instructions for each experiment.

Step 4: Start experiment(s)

To start a single experiment, simply enter go under that experiment.
To start multiple experiments, enter go under each experiment #. The first experiment will start immediately and the rest will be queued and run sequentially. To check how many experiments are queued, click the blue triangle button next to the FID status display (see image below). An "Acquisition status" window opens and shows the current running exp. and number of exps. queued.

To stop an experiment, depending on which experiment to be stopped, do the following:

Enter aa under any experiment to stop the current running experiment. If there are queued experiments, the next one starts immediately after the current one is stopped. Enter aa multiple times to kill the rest of the experiments.
To stop a specific experiment, i.e. exp3, which is queued behind other experiment(s), first enter jexp3 to join experiment 3. Then, enter sa (NOT aa) to remove the current displayed experiment among the queued experiments. If exp2 is running, sa under exp3 has on effect on exp2.

For all 2D (or any arrayed experiment), watch for ADC or receiver overflow immediately after the start of data collection.

In arrayed experiments such as 2D's, a fixed gain (not autogain) must be set. Watch the receiver overflow light on the VT monitor next to the workstation and the ADC overflow error message immediately after the experiment starts. The default value works most of the time unless there is an extremely strong 1H signal in your sample. With a gain above 20, it makes only small differences in signal/noise.
If the receiver overflows (red light blinks on VT display) or ADC overflow message is seen above the command area anytime during the experiment except during the dummy scan period, it is likely the data are ruined. Stop the experiment (enter aa), check the current gain (gain?) and reduce gain by 2-4 at a time (gain=22, etc), enter go and repeat the procedure until the overflow disappears.

H. Zhou Updated 04/2012