Process pull-down menu

A further integral mode is available with Integration in the Process pull-down menu. This, however, will simply replace the spectrum by its integral. Its main purpose is to inspect the integral of the whole spectrum before actually and interactively execute the integration. Use the Help option for more informations if necessary. 

From the Process pull-down menu choose the Integration option. Using the... 

Prior to Fourier transformation the actual number of measured data points and the total number of data points to be transformed may be defined. With ID WIN-NMR the following definitions are valid and may be inspected for the actual data file by selecting the Zero Filling... option in the Process pull-down menu. 

With 2D experiments the situation is a little more complicated as the size of the overall digitised matrix depends on the number of time increments in tl as well as parameters specific to the 2D acquisition mode. Nevertheless, a digitised matrix of TD(2) X TD(1) complex data points is acquired and stored. Similar to ID the effective number o measured data points used for calculation TD(used) and the total number of data points SI to be transformed in t2 and tl may be defined prior to Fourier transformation. These parameters may be inspected and defined in the General parameter setup dialog box accessible via the Process pull-down menu. With 2D WIN-NMR the definitions for TD(2) and TD(1) are the same as for TD with ID WIN-NMR. However, unlike ID WIN-NMR, with 2D WIN-NMR SI(2) and SI(1) define the number of pairs of complex data points, instead of the sum of the number of real and imaginary data points. Therefore the 2D FT command (see below) transforms the acquired data of the current data set into a spectrum consisting of SI data points in both the real and the imaginary part. 

Fourier transformation in ID WIN-NMR is accomplished by choosing either the FT command in the Process pull-down menu (Fig. 5.3) or by simply clicking the FT button in the button panel. 

With the command Phase Correction in the Process pull-down menu the button panel is switched into Phase mode (Fig. 5.4) and a semi-automatic or fully manual phase correction may be performed. 

Fig. 5.4 Button panel for phase correction (left) opened by choosing the Phase Correction option in the Process pull-down menu (right).

Load the raw data of the ID H experiment measured for peracetylated glucose D NMRDATA GLUCOSE 1D H GH 002001.FID and perform a Fourier transformation. Use either the FT button in the button panel or from the Process pull-down menu choose the FT option. In the DC Correction dialog box click on the No button. Note that the calculated spectrum is incorrectly phased. Use the dual display option to compare this spectrum, showing the ring protons, with the correctly phased spectrum D NMRDATA GLUCOSE 1 D H GH 002999.l R. Exit the dual display and from the Process pull-down menu choose the Phase Correction option. The... 

With 2D WIN-NMR, 2D Fourier transformation may be accomplished with the commands xfb, xtrf, xf2 and xfl accessible via the Process pull-down menu (Fig. 5.5). 

Fig. 5.5 Process pull-down menu of 2D WIN-NMR used to initialize a 2D FT.

For 2D data which need no phase correction the PHmod parameter in FI, available in the General parameter setup dialog box opened via the Process pull-down menu, must be set to me if a magnitude, or to ps if a power spectrum should be calculated. Use the Help tool for more informations. 

For 2D spectra to be displayed in phased mode, choose the Manual phase correction option from the Process pull-down menu of 2D WIN-NMR. This will also change the info field of the button panel and disable some of the panel buttons (Fig. 5.7). 

Fig. 5.7 Buttons accessible with the Manual phase correction option in the Process pull-down menu of 2D WIN- NMR (left). Additional button panel for adjusting the reference point and for switching the 2D display off (right).

Load the raw data obtained for peracetylated glucose with the 2D TOCSY experiment D NMRDATA GLUCOSE 2D HH GHHTO 001001.SER and perform a 2D FT following the guidelines given above. Enter the Manual phase correction option in the Process pull-down menu and perform a phase correction in F2 and Ft according to the procedure outlined above. Try to phase all peaks to positive absorption and store the spectrum (... 001001. RR). 

Note If the FT in ti has been applied with PHmod for Fl accidentally set to no, choose the Magnitude spectrum submenu from the Process pull-down menu and select the command of Fl columns [xfim] for a subsequent magnitude calculation. 

Load the ID H FID of peracetylated glucose D NMRDATA GLUCOSE 1D H GH 001001. FID, increase its vertical scale and inspect its last part on the screen. Notice the deviation of the mean FID from the zero horizontal line switch back and forth between the real and the imaginary part of the FID to recognize a DC offset between the two parts. From the Process pull-down menu choose the DC Correction option and apply a DC correction. Inspect the last part of the FID again. Fourier transform the FID with/without a DC... 

With 2D WIN-NMR zero filling is defined simply by setting SI for the F2 and Fl dimension in the Parameters dialog box opened with the General parameters setup command in the Process pull-down menu prior to Fourier transformation. 

With 2D WIN-NMR forward and backward LP is accessible via the General parameter setup command in the Process pull-down menu where the parameters ME mod, SI, TD or TDeff, TDoff, NCOEF and LPBIN may be selected and edited (Fig. 5.24). 

These options are available only with ID WIN-NMR via the FID Shift..., Adjust Point and Zero Filling... options in the Process pull-down menu. Use the Help tool for more information about these options, their dedicated panel buttons and how to use them. 

Adding or subtracting FIDs is only possible with 1D WIN-NMR and is accomplished with the File Algebra option in the Process pull-down menu. A dialog box allows you to select the second file and to specify whether FIDs or spectra should be added/subtracted. At the same time the screen is horizontally split into three regions with the original spectrum at the top, the second spectrum in the middle and the result of the arithmetic operation at the bottom. A new button panel appears where several specific options are available (Fig. 5.27). In contrast to the Dual Display function, available in the Display pull-down menu and discussed in chapter 4, more options exist with File Algebra, i.e. to store the result or to move one of the traces with respect to the other. Use the Help tool for more information. 

Load the H spectrum of peracetylated glucose D NMRDATA GLUCOSE 1D GH 001999.1R. From the Process pull-down menu choose the File Algebra option. In the dialog box select Spectrum Type and use the expanded H spectrum D NMRDATA GLUCOSE 1D GH 002999.1R as the second spectrum. Explore the functions of the buttons in the new button panel and try out the effect of the various options. Use the Help tool if necessary. 

The Adjust Point option available from the Process pull-down menu allows you to move single points in y - dimension to correct faulty data points, e.g. spikes. The same function has alreday been used to correct "wrong values in the FID. Adjust Point should not be used to purify your sample, by removing the residual signals of impurities or of a solvent. 

In many cases, 2D spectra contain asymmetric artifacts introduced by the experiment. In order to get rid of these unwanted features, some additional processing tools exist and may be performed with 2D WIN-NMR. Corresponding function buttons become accessible via the Manipulation command in the Processing pull-down menu of 2D WIN-NMR (Fig. 5.30). 

In ID WIN-NMR the processing and analysis tools are available from the Process or Analysis pull-down menus in the menu bar. The Process pull-down menu is context sensitive such that before the Fourier transformation only time domain processing functions are available whilst after Fourier transformation the Process pull-down menu is updated to include frequency domain related processing functions. The ID WIN-NMR Process and Analysis pull-down menus are shown in Fig. 3.5. 

The phase correction of a 2D spectrum follows essentially the same procedure as a ID spectrum except that the phase correction for the rows, the f2 dimension, and columns, the fl dimension, must be executed separately. The following discussion describes the phase correction in the f2 dimension the phase correction of the fl dimension is achieved in a similar way. After Fourier transformation the Manual phase correction command is selected from the Process pull-down menu. The phasing procedure is divided into three steps. 

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