Chapter 3 Peak Detection and Labeling

 

 

Problem

 

Suggested Actions

 

 

 

 

 

 

 

Partially resolved peaks

 

If peaks represent two compounds, and you want both

 

 

not detected

 

peaks labeled, do either of the following:

 

 

 

 

• Set %Max Peak Area to 0, then adjust the %Base

 

 

 

 

Peak Intensity until peaks are detected.

 

 

 

 

• Click the Peak Processing tab, then change the

 

 

 

 

default Integration Baseline Setting from

 

 

 

 

Valley-to-Valley to Valley-to-Baseline.

 

 

 

 

 

 

 

 

 

If peaks represent partially resolved isotopes, and you

 

 

 

 

want to label and detect the average mass, decrease the

 

 

 

 

Mass Resolution setting until the isotopic envelope is

 

 

 

 

detected.

 

 

 

 

 

 

 

 

3

 

 

4. If you see more than one of the problems listed above in a

 

 

 

spectrum, you can adjust peak detection parameters for

 

 

 

any or all detection ranges (referred to as setting

 

 

 

 

parameters locally) by doing the following in the order

 

 

 

 

listed:

 

 

 

 

• Disable Use Resolution Dependent Settings.

 

 

 

 

 

 

 

• Click the Advanced tab.

 

 

 

 

• Select a detection region that is exhibiting the

 

 

 

 

problem.

 

 

 

 

• Adjust the local settings to fine tune detection.

 

 

 

 

• Click OK.

 

 

 

5. If peak detection is still not acceptable, adjust the

 

 

 

 

remaining peak detection parameters, as described in

 

 

 

 

Section 3.2.3, Setting Peak Detection Parameters.

3-10 Applied Biosystems