Method and apparatus for ion fragmentation in mass spectrometry

A method for acquiring fragment ion spectra, via fragmentation of analyte ions in reactions with radical species, comprising:

• generating the analyte ions in a gas phase from a first sample;
• generating the radical species in a gas phase from a second sample;
• mixing the analyte ions and the radical species at substantially atmospheric pressure conditions to produce fragment ions;
• introducing at least part of the fragment ions into a mass spectrometer;
• and
• measuring mass to charge ratios of the fragment ions in the mass spectrometer.

A system for mass spectroscopy, comprising:

• a gas-phase analyte ion source configured to generate gas-phase analyte ions;
• a gas-phase radical species source separate from the gas-phase analyte ion source and configured to generate gas-phase radical species;
• a mixing region where said gas-phase analyte ions and said radical species are mixed at substantially atmospheric pressure to produce fragment ions of said analyte ions;
• a mass spectrometer having an entrance where at least a portion of said fragment ions are introduced into a vacuum of the mass spectrometer;
• and
• a detector in the mass spectrometer which determines a mass to charge ratio analysis of the fragment ions.