Charge-stripping of multiply-charged ions

摘要

A method of mass spectrometry or ion mobility spectrometry is disclosed wherein a sample is ionised by an electrified sprayer 4 so as to produce multiply charged analyte ions 5 of a first polarity in gas-phase. A reaction region 14 is provided downstream of the electrified sprayer 4 and is maintained substantially at atmospheric pressure and is maintained substantially free of electric-fields. A gas flow 6 is provided from said electrified sprayer 4 to said reaction region 14 such that the gas flow 6 carries the analyte ions 5 into the reaction region 14. Free electrons or reagent ions 7 of a second polarity are generated in the reaction region 14, wherein the second polarity is opposite to said first polarity. The free electrons or reagent ions 7 are then reacted with the analyte ions 5 in the reaction region 14 so as to reduce the charge state of the multiply charged analyte ions 5 and thereby produce charge-reduced analyte ions 9.