The spectrum Precursor Detector node identifies additional precursors within the isolation window of the precursor spectrum. You can use this node to identify chimeric or mixed spectra by connecting it to any spectrum sending node, such as the Spectrum Selector node. Use this node with the Sequest HT node or the MSPepSearch node.
The Precursor Detector node keeps the original precursor, which is assigned by the Spectrum Selector node, and adds additional precursors that are contained in the mass spectrometer’s isolation window (shown in the yellow section of the Precursor Isotope Pattern pane).
The following table describes the Precursor Detector node parameters.
Parameters | Description |
|---|---|
S/N Threshold | Peaks with a signal to noise value below the specified threshold are removed and are not used for isotope pattern recognition. Minimum value 0; Maximum value 1000; Default 1.5 Da |
S/N Threshold for most abundant peak | Only precursors having a peak above the specified S/N threshold are stored. |
For an MS/MS Spectrum Info pages that includes a chimeric spectra, see The MS/MS Spectrum Info page.
For information on using the node in a workflow, see Including Spectra Export in a Workflow.