The first step in profiling a sample is to identify a compound in that sample. To do this, you need to match the compound signatures from the software with patterns in your sample spectrum. There are several ways that you can do this.
To identify specific compounds
-
Select at least one compound set in the Compound Sets view (see “Compound Sets (Sidebar)”).
-
Locate a compound in the Compound Table that you believe is present in the sample and select it (see “Compound Table”).
-
For each cluster, compare the shape of the preview line (light blue) and the spectrum line (black) and decide whether it is reasonable that the preview line could be contributing to the spectrum line in the displayed region.
-
If the shape appears reasonable, click the preview line, and adjust the resulting shape by determining appropriate heights and cluster locations for the compound (see “Concentrations and Compound Fits”.
-
If the shape does not appear reasonable, continue by selecting another compound in the Compound Table.
To find possible compounds contributing to a specific peak
-
Select at least one compound set in the Compound Sets view (see “Compound Sets (Sidebar)”).
-
Right-click on the peak, and click Search for Compounds Near x.xx ppm.
-
In the Compound Table, select one of the listed compounds to display the preview line and Cluster Navigator for the compound (see “Cluster Navigator”).
-
Compare the shape of the preview line (light blue) and the spectrum line (black) and decide whether or not it is reasonable that the preview line could be contributing to the spectrum line in the displayed region.
-
If the shape appears reasonable in the region near the cluster that you are investigating, use the Cluster Navigator to verify that the other clusters for the compound also appear to match reasonably well (see “Cluster Navigator”).
-
If all clusters appear reasonably well-matched, apply an automatic fit, then adjust the fit for the compound as needed (see “Concentrations and Compound Fits” and “Fit Automatically”).
-
If the shape does not appear reasonable, continue evaluating the rest of the compounds in the list.
-
When you have finished with the filtered list, clear the frequency filter to continue your analysis with the full compound list (see “Quick Searches”).
-
If none of the compounds in the list of potential candidates provides a reasonable shape near the peak that you are investigating, consider the possibility that the compound responsible for the peaks is not in your compound library, or not in your currently selected compound set.
To identify all compounds contributing to a particular region
-
Select at least one compound set in the Compound Set Panel (see “Compound Sets (Sidebar)”).
-
Select a region in the Spectrum Graph (see “Select Region”).
-
Search the Compound Table for compounds in the selected region (see “Quick Searches”).
-
In the Compound Table, select one of the listed compounds.
-
Compare the shape of the preview line (light blue) and the spectrum line (black) and decide whether or not it is reasonable that the preview line could be contributing to the spectrum line in the displayed region.
-
If the shape appears reasonable in the region near the peak that you are investigating, use the Cluster Navigator to verify that the other clusters for the compound also appear to match reasonably well (see “Cluster Navigator”).
-
If all clusters appear reasonably well-matched, apply an automatic fit, then adjust the fit for the compound as needed (see “Concentrations and Compound Fits” and “Fit Automatically”).
-
If the shape does not appear reasonable, continue evaluating the remainder of the compounds in the list.
-
When you have finished with the filtered list, clear the frequency filter to continue your analysis with the full compound list (see “Quick Searches”).