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Simplified 2-D Processing

Standard 2-D processing requires a few mouse clicks. If the palette is closed you can choose Tools > Palette. The palette is, however, optional, because the same commands can be found into the Process menu.

To Process a Generic 2-D Spectrum:

Step 1

Open the file containing the spectrum.

If your spectrum corresponds to a folder, choose any of the files at the top level of that folder. iNMR will then show the raw, time-domain, data.

Step 2

Click the gears icon twice.

The gears icon is one of the few enabled icons when the spectrum is in time domain. It performs zero-filling, weighting and Fourier Transform. A 2-D spectrum requires two FT operations, therefore you'll click this icon twice. When the spectrum has been transformed into the frequency domain, the gears icon is disabled.

When processing a new Varian or Bruker spectrum, iNMR automatically creates suitable parameters. In other cases, or when you prefer custom processing, open the dialog Process > Fourier Transform and set the parameters manually.

Step 3

Adjust the amplification, if necessary.

If you can't see the spectrum, double click inside the main window. If you can see the spectrum, you may still want to press the plus key to reveal more peaks or the minus key or to hide the noise.

Step 4

Correct the Phase.

If the spectrum is phase-sensitive, it is necessary to correct the phase. Click the corresponding icon (dispersion signal with a gear) to force the automatic correction. You can further refine it manually (click the similar icon without the gear). If the spectrum isn't phase-sensitive, no correction is necessary and iNMR displays it in absolute value. This representation can also be chosen manually, with the command Process > Magnitude.

Step 5

Correct the Baseline.

Click the icon at the bottom: two peaks over a slope and a gear.

Step 6

Add the external Projections.

If you have a 1-D equivalent of the same sample (or two spectra, in the case of hetero-correlated-2-D), open them, then return to the 2-D window and:

Choose Format > Overlay.

Check the box near the name of the 1-D file to use as external projection.

Click “Fit Intensity”.

In the two projections are different, repeat for the second projection.

Step 7

Calibrate the X axis.

Choose Format > Axes and Scales, then click Reference.

To copy the calibration from the 1-D spectrum, select its name from the bottom menu.

Otherwise enter the correct central frequency.

There are many other ways to calibrate a frequency axis, if you are interested.

Step 8

Calibrate the Y axis.

If the 2-D spectrum is homonuclear and the spectral width is the same along both axes, they are already kept in sync by the program. If, instead, the spectrum is heteronuclear, repeat the process described above, but for the Y axis.

Additional operations are available, but not always necessary. In time domain: solvent suppression and linear prediction. In frequency domain: symmetrization, noise removal, binning, integration, peak-picking.

Related Topics

Reducing the Number of Dimensions

Standard Workflow for Routine Spectra


External Tutorials

3-D Processing step-by-step