Patent ID: 6727497
Filing Date: 2004-04-27
Classification: H01J

Abstract:
A device for determining the identity and concentration of macromolecules in a sample analyte solution containing at least one macromolecule in at least one solvent, said device comprising:a) an electrospray ionization source for producing a plurality of multiply charged analyte droplets of the sample analyte solution in a flow of bath gas, wherein at least partial evaporation of solvent from the droplets results in the formation of a plurality of multiply charged macromolecule particles in the flow of bath gas; b) a charge reduction chamber cooperatively connected to the electrospray ionization source for receiving the flow of bath gas, charged analyte droplets and multiply charged macromolecule particles, wherein the macromolecule particles remain in the charge reduction chamber for a selected residence time; c) a radioactive source operationally connected to said charge reduction chamber that emits particles into the charge reduction chamber, wherein said particles emitted by the radioactive source ionize at least a portion of the bath gas to generate bipolar ions within at least a portion of the volume of the charge reduction chamber, wherein said bipolar ions react with the macromolecule particles having multiple charges to reduce their charge state; d) a radiative flux attenuator element positioned between the charge reduction chamber and the radioactive source for reducing the flux of particles into the charge reduction chamber; and e) a mass spectrometer operationally connected to said charge reduction chamber, for analyzing said macromolecule particles; wherein the residence time of droplets, macromolecule particles or both and the concentration of bipolar ions in the charge reduction chamber is adjusted to control the charge distribution of the macromolecule particles.