Chapter 3 Peak Detection and Labeling

Using the

Deisotopefunction

3

To use the Deisotope function:

1.Display the spectrum trace of interest.

2.Make sure peak detection thresholds are set low enough to detect the monoisotopic peak before deisotoping. If the detection thresholds are not set low enough, adjust them. For information, see Section 3.2.3, Setting Peak Detection Parameters.

If you are analyzing digest data, set %Max Peak Area to 0 before deisotoping to ensure that all peaks of interest are detected. For more information, see Section 7.2.3, Detecting Peaks from Complex Digests.

3.If multiply charged peaks are present, convert to a singly charged spectrum. See Section 5.10, Converting to a Singly Charged Spectrum (Mariner Data Only).

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

5.From the Peaks menu, select Peak Deisotoping.

The Deisotoping dialog box (Figure 3-18)is displayed.

Figure 3-18 Deisotoping Dialog Box

6.In the Adduct text box, type the adduct that is the charge-carrying species in the spectrum you are examining.

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