Patent ID: 6987264

Claim:
An apparatus for analyzing chemical species, comprising: a. an ion source for operation at substantially atmospheric pressure to produce ions from a sample substance; b. a vacuum system with at least one vacuum pumping stage; c. a mass analyzer and detector configured in said at least one vacuum pumping stage; d. at least two multipole ion guides configured to be sequentially located and substantially adjacent to each other so as to be continuous in said at least one vacuum pumping stage wherein at least a portion of each of two of said at least two multipole ion guides is positioned in at least one vacuum pumping stage, wherein the background pressure in said vacuums pumping stage is at least 1 millitorr which is sufficiently high such that collisions occur between said ions and neutral gas molecules in said at least two multipole ion guides; e. means for conducting mass to charge selection in at least one of said multipole ions guides; and f. means for conducting collisional induced dissociation ion fragmentation in at least one of said multipole ion guides, g. RF and DC voltage sources applied to each of said at least two multipole ion guides, wherein said RF and DC voltages are controlled independently of each other.