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How to Reference the Scale

You can change the scale reference at any time. We suggest, however, that you to preform this operation, when possible, on the spectrometer. In this way all your data will be correct (iNMR never writes into the original files).

There are many ways to calibrate the frequencies

Step 1

Right-click the reference peak. From the contextual menu, choose Reference Scale. Insert the correct frequency value for your peak and click on OK.

If you are referencing the spectrum against a solvent peak, you can choose one of the stored values from the menu.

In the case of a homonuclear correlation spectrum, both frequency axes are corrected by this operation. In the heteronuclear case, only the horizontal axis is corrected. The following method can be used to calibrate the vertical axis.

Step 2

Put a mark at a frequency you know the value of. Create a vertical mark (with Alt Gr-click or ⌘-click) to calibrate the X axis or an horizontal mark (with Alt-click) to calibrate the Y axis. Choose Format > Axes & Scales, click Reference and continue as above.

This method can be more accurate, because iNMR doesn't locate the top of the nearest peak, like in the first method, but simply looks at the frequency of your mark. Drag the mark exactly in the middle of your reference peak.

Step 3

If you know the correct position of the transmitter (the center of the spectrum) along the ppm scale, you can directly choose Format > Axes and Scales, then click Reference, etc...

Step 4

If you have already calibrated the scale into another window, and if the document you are working on has the same spectral width, you can copy the calibration.

Choose Format > Axes and Scales, click Reference, then choose the reference window from the menu at the bottom.

Step 5

You can copy the reference from one document to many other open documents with a single operation.

Select the reference document window.

Choose Format > Overlay.

Click the check-buttons at the left to select the documents whose scale you want to correct or put a check mark into the shortcut button “All Windows”.

Click Force Same Scale.

Step 6

You can use the console command refer.

Step 7

The dialog Process > Process Folder also contains the functionality given by the command refer.

Should you need to change the values for the spectrometer frequency and the spectral width, open the dialog Edit > Metadata.

How to Customize the List of Solvents on the Mac

  1. Copy the file /Applications/iNMR/Contents/Resources/txt/solvents.txt into the folder ~/Library/Application Support/iNMR/.
  2. Modify the copy.

Related Topics

Comparing Two Spectra in Two Windows

Generating the List of Chemical Shifts and Coupling Constants


Web Tutorial

Visual Guide to the Frequency Scale