Chapter 7 Data Explorer Examples

7.2.3Detecting Peaks

from Complex Digests

 

Overview Complex digests often contain hundreds of peaks which may

 

 

have relatively low signal-to-noise ratios. To quickly screen out

 

 

noise and detect peaks of interest:

7

 

• Noise filter/smooth to remove initial noise.

 

• Set initial peak detection thresholds low enough to detect

 

 

all peaks, to ensure that monoisotopic peaks are detected

 

 

for proper deisotoping.

 

 

• Deisotope to identify isotope peak clusters. The

 

 

deisotope function amplifies peak intensity based on the

 

 

 

total area of all peak areas in the isotope cluster. It does

 

 

not amplify noise peaks.

 

 

• Increase peak detection thresholds to eliminate noise

 

 

peaks.

 

 

Figure 7-18represents a spectrum trace from a digest.

 

 

Overlapping Peak Labels are enabled to illustrate the large

 

 

number of peaks detected in the spectrum (over 300 peaks

 

 

contained in the peak list displayed in the Output window).

 

 

 

 

 

 

Figure 7-18 Digest with Several Hundred Peaks

Detected (Allow Overlapping Labels Enabled)

7-18 Applied Biosystems