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Suggested Workflow for J-Resolved Spectra

In most 2-D experiments the two scales on the orthogonal sides both measure a chemical shift. They are called correlation experiments. Different is the case of J-Resolved Spectroscopy, where one of the scales measures the coupling constants only. The processing workflow is similar, with a few extras. At the end, the projection along f-2 contains a single peak per nucleus, as if they have been decoupled, while the traces along f-1 contain the multiplet patterns. The total number of peaks is the same as in the 1-D spectrum, but they are resolved in two dimensions.

Step 1

Open the Edit > Metadata dialog.

In the first column (f-1), set the nucleus to “0-J” and the observe frequency to 1 MHz.

This first step is a matter of tastes and you can skip it. After the suggested modification, you'll have no problem with the projections and the scales.

Step 2

Fourier Transform twice.

Use a squared sine bell (shift = 0) in both dimension. Normally you'll want to increase the resolution: zero-fill in both dimension, but more in f-1 than in f-2. The classical version of the experiment cannot be represented in absorption mode: select “Magnitude” in the final FT.

Step 3

Open the Reference Spectrum.

You certainly have the traditional 1-H spectrum of the same sample, possibly acquired with an identical spectral width. Keep it open. We'll use it as an external projection and also to reference the frequency scale of our 2-D plot. Now let's return to the latter.

Step 4

Calibrate the Frequency Scale.

After the second FT, the X dimension of our 2-D experiment corresponds to the J-dimension. Open the dialog: Format > Axes & Scales. Set the central frequency to zero. Click on “set”. Move to the last panel and transpose the plot. Return the the first panel to calibrate the other scale. You can use the menu “Copy Reference from: select an open window” and select the 1-D reference. This trick will work if the frequency range is identical in the two cases.

Step 5


Each component of each mutliplet falls at its natural frequency, given by the sum of the chemical shift and of the coupling constants divided by 2. We want, however, that all the components are realigned at the central frequency of each multiplet, removing the J contribute. The command for the task is Process > Symmetrize > Tilt.

Step 6


After tilting, the peaks acquire an oblique shape. You can make them symmetric and sharper with Process > Symmetrize > Sym J resolved. Like all non-linear methods, it removes a lot of nasty signals and artifacts but could, at the same time, create its own artifacts. This operation is optional, and often convenient.

Step 7

Add the external projection.

Use the Overlay Manager.

Step 8

Zoom and Cut.

Hide the empty regions around and between the important peaks, using the tools “zoom” and “cut”.

Step 9

Adjust the Contour Plot.

Open the dialog “Format > Levels & Colors”. Set the spacing to circa 1.2, remove the negative levels, increase the number of positive levels until all the splittings are shown.

Related Topics

About Processing

2-D Processing