Applied Biosystems Data Explorer 4 Series User Manual page 134

Chapter 3 Peak Detection and Labeling
Effect of Minimum
3
Charge state
determination
troubleshooting
3-36 Applied Biosystems
The Minimum Intensity setting on the Advanced Settings tab
can also determine how charge states are determined for a
Intensity
peak, because it determines if the software can find a match
for a peak. Figure 3-12 illustrates two peaks correctly labeled
with charge state 1.
Figure 3-12 Minimum Intensity Set Correctly
If you increase the Minimum Intensity setting to 85 in the
example shown in Figure 3-12, the software cannot determine
a charge state for the first peak (Figure 3-13). This is because:
• The increased threshold suppresses the detection of the
236.6 m/z peak.
• When the software evaluates the peak at 235.6 m/z, it
does not find a peak at the appropriate peak spacing for
charge state 1, and therefore determines that the peak
has no calculated charge.
Figure 3-13 Minimum Intensity Set Incorrectly
See Table 9-12, "Charge State and Isotope Determination
Troubleshooting—Mariner Only," on page 9-18.