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DOSY for beginners

To process a DOSY successfully you should be familiar with 1-D and 2-D processing.

Set Up iNMR:

Step 1

First set up iNMR for running scripts, if it's not already set up. If you have a Bruker spectrometer, add the file DOSYbruker.lua into your folder of scripts. If you have a Varian spectrometer, add the file DOSYvarian.lua instead.

Set up the spectrum:

Step 2

Open the spectrum with iNMR. Open the dialog Edit > Metadata. Under the column f1, change the name of the nucleus to “0-.” (zero dash dot). Do not edit the nucleus under the column f2. Close the dialog.

Step 3

From the script menu, select DOSYbruker or DOSYvarian, according to your case. A message will appear into the console, like “19 values extracted and converted”. The number must correspond to the number of rows in your spectrum.

Step 4

Extract the bottom row of the 2-D plot. Perform FT (without weighting) and phase correction. Close the extract. Apply the same FT on the whole matrix.

Perform DOSY-specific processing:

Step 5

Open the dialog Process > DOSY > Mono Exponential. For the first attempt, choose “Logaritmic Scale”. Click on OK.

Optimize processing:

Step 6

Observe the result. Maybe you can reduce the spectral width, thus increasing the resolution. This is more important in the vertical scale. Take a mental note of the narrowest limits of the scale that encompass all the peaks.

Step 7

Start over with the commands: File > Reload; Process > Fourier Transform; Process > DOSY > Mono Exponential. Now you can try changing a few parameters. Their meaning is explained here.

Step 8

If you are not satisfied with the new result, return to step 7 and change the parameters again.

Related Topics

DOSY reference manual

example data set