Chapter 4 Examining Chromatogram Data
NOTE: Before you can subtract spectra, you must first specify spectra to be added.
6. Select spectra to subtract as described in step 4.
7. Select the Add/Subtract mode:
• Average— Spectra in each list are averaged before the addition or subtraction occurs.
• Accumulate— Spectra in each list are summed before the addition or subtraction occurs.
NOTE: If you select Accumulate mode, include at least the same number of spectra in the Subtract range that you include in the Add range. For example, if you include spectra 775 to 794 in the Add range, make sure to include 20 or more spectra in the Subtract range.
8. Click OK.
4
The subtracted baseline trace is displayed, with the added and subtracted spectrum numbers in the trace label. Also, if the retention time labels are displayed, the retention time range is included in the trace label.