Chapter 4 Examining Chromatogram Data

4.5Adding and SubtractingRaw Spectra Within a Data File
Adding and subtracting spectra

Use the Add/Subtract Spectra command to manipulate raw spectra within a single data file.

NOTE: To manipulate processed spectra, spectra from different data files, or spectra acquired under slightly different instrument calibrations, use Trace Arithmetic. For more information, see Section 5.12, Adding and Subtracting Raw or Processed Spectra from the Same or Different Data Files (Dual Spectral Trace Arithmetic).

To add and subtract spectra:

1.Click the Spectrum window to activate it.

2.Select Duplicate Active Trace from the Display menu to keep the original data displayed after processing.

3.From the Process menu, select Add/Subtract Spectra.

The Add and Subtract Spectra dialog box is displayed (Figure 4-9).

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