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Using the DP routine

Using the DP routine


Using the Define Peaks Subroutine (DP)

This subroutine allows peaks to be selected manually with the mouse, and provides options for displaying peak labels. See also Peak Picking (PP).

The features described here refer to NUTS versions 971227 and later. Numerous changes were made to the DP routine starting with this version, including automatic avoidance of peak overlap and the ability to place the labels at the top of the page.

(Note that DP is not included in NUTS Lite. However, peaks can still be labeled using the PP command.)


Enter the DP routine from the Tools menu or by typing DP.

To select peaks manually with the mouse, place the cursor at the top of the peak and click once with the left mouse button. By default, NUTS snaps to the closest peak maximum, but this can be turned off from the Edit menu.

Peaks can also be selected automatically by typing A or from the Edit menu. Peaks exceeding the Minimum Height threshold (MH) are selected in the same manner as for PP.

A small, red line shows each peak which has been selected.

All selected peaks can be cleared by typing C or from the Edit menu. A selected peak can be deleted by placing the cursor on the peak (don’t press the mouse button) and typing K (kill).


To view information for a selected peak, place the cursor near that peak and click with the right mouse button, which displays the box shown here. (Users with a single-button mouse should hold down the shift key and click the mouse button.)

The peak’s frequency in Hz and ppm is displayed in the box labeled "Horizontal". (The box labeled "Vertical" is for the second dimension of 2D data. The values for Area/Volume refer to the volume of 2D crosspeaks. These items are not relevant in this case.)

By default, NUTS will label all peaks with chemical shift in ppm, but it is possible to display the text label instead for a chosen peak, by checking the "Show info field only" box. It is also possible to label all peaks with Hz or text — see below.

The peak label can be displayed either vertically or horizontally using the check box labeled Vertical Font. The default orientation of all labels can be set in the nuts.ini file. Note that Macs do not have the ability to display fonts vertically on the screen.

The list of selected peaks, including peak labels, is saved with the spectrum, in the file tailer. It is sometimes helpful to enter extra text in the text field for future reference, but not display all of that text on a plot. The check box labeled "Show first argument only" is used to display only the beginning of the text label, up to the first space encountered.


Display of peak labels is toggled on and off from the Edit menu or by typing Ctrl-P (which is active even after leaving the DP routine). By default, NUTS displays the chemical shift, in ppm, as the label. The other options are peak frequency in Hz (subcommand H, available from the Edit menu) or text label (subcommand I, also available from the Edit menu as Show Peak Information Label).

NUTS attempts to avoid overlap of peak labels, but this may not be possible for a very crowded spectrum. Labels can be placed either at the top of the page (shown above) or just above each peak, as shown below. This can be set as the default for all peaks in the nuts.ini file, or can be set for individual peaks by displaying the peak’s information dialog box and selecting/unselecting "Labels at page top".

Individual labels can be moved by placing the cursor on the chosen label, holding down the left mouse button and dragging the label. Note that usually the label takes up less space when printed than on the screen, due to the increased resolution on the printer. Selecting a smaller font size, such as 6, will also help in avoiding overlap of labels.

A peak list can be placed into the clipboard by selecting Type Peak List to Clipboard from the Edit menu (subcommand T) from which it can be pasted into a text editor for printing or displayed on the screen by typing Ctrl-B. The peak list can also be saved to a text file from the File menu.


Exit the DP routine by typing <Enter>. The red lines and boxes around the labels are no longer displayed. Here, 2 of the peaks have text labels displayed, using horizontal font, positioned above the peaks rather than at the top of the page. Each of these options was selected from within the peak information dialog box.

After exiting DP, the set of peaks is still defined, and can be edited by re-entering the DP routine. They also still exist even if a new data file is opened, whether or not peaks exist at these frequencies in the new spectrum.

Display of the labels can be toggled on and off with Ctrl-P. Labels for peaks which have the "Show info field only" box selected will continue to be displayed even if display of labels is turned off.

Return to description of DP routine

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Last updated: 12/29/97.