Peak List

 

 

2. Select Enable Peak List Filter, then select:

 

 

 

 

 

Filter Type

Description

 

 

 

 

 

 

Monoisotopic

Labels the peak of the lowest detected mass in an isotope

 

 

 

envelope. Before applying filtering, set the values in Peak

 

 

 

Processing detection parameters to accurately detect and label all

 

 

 

peaks in the isotope envelope with the correct charge state. If the

 

 

 

parameters are not correctly set to yield correct charge states for

 

 

 

all peaks, the monoisotopic peak may not be correctly labeled.

 

 

 

See Section 3.2.5, Charge State Determination and Examples, for

 

 

 

more information on setting parameters.

 

 

 

Monoisotopic filtering is useful on isotope clusters where the

 

 

 

approximate elemental composition and isotopic ratios are not

 

 

 

 

 

known, for example, in PSD analysis (where the precursor ion

 

 

 

filtering enhances the precursor ion isotope intensity relative to the

 

3

 

rest of the cluster), or in a spectrum that contains molecules with

 

 

very different elemental compositions.

 

 

For most applications, especially peptide analysis, the deisotoping

 

 

 

function yields more accurate results than monoisotopic peak

 

 

 

filtering. See Section 3.4, Deisotoping a Spectrum.

 

 

 

 

 

 

Charge State

Labels the peaks with the selected charge state (z). If you select a

 

 

 

charge state of 0, the software displays mass labels only on peaks

 

 

 

for which the software could not determine a charge state.

 

 

 

CAUTION: A zero value in the Spec Peak list does not indicate a

 

 

 

charge state of zero. It indicates that the software could not

 

 

 

determine the charge state.

 

 

 

 

 

 

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