Charge state of precursor ion is important information for various MS data analsysis,
and indeed Mass++ uses charge information for peptide identification.
But the precursor charge which is written in original raw data doesn't exported to mzML/mzXML by Mass++.
I think we need to write out precursor charge at {MzmlManager|MzXmlManager}::writeSpectrum().
Charge state of precursor ion is important information for various MS data analsysis, and indeed Mass++ uses charge information for peptide identification. But the precursor charge which is written in original raw data doesn't exported to mzML/mzXML by Mass++. I think we need to write out precursor charge at {MzmlManager|MzXmlManager}::writeSpectrum().