Patent ID: 6897439

Claim:
An apparatus used for analyzing chemical species comprising: (a) an ion source operated at or near atmospheric pressure which produces ions from solution and delivers said ions into a first vacuum pumping stage through an orifice; (b) two or more vacuum pumping stages with means for pumping away gas in each vacuum stage whereby each successive vacuum pumping stage has a lower background pressure than the previous pumping stage; (c) a mass analyzer and detector located in one or more of the vacuum pumping stages; (d) a multipole ion guide which begins in one vacuum pumping stage and extends contiguously into one or more subsequent vacuum pumping stages, said multipole ion guide consisting of a multiple of equally spaced parallel poles extending the length of said ion guide, said multipole ion guide is positioned in said vacuum pumping stages to guide ions delivered from said ion source through a portion of said vacuum stages; (e) means for applying voltages to said poles of said multipole ion guide; and, (f) means for controlling the frequency of said voltages applied to said poles of said multipole ion guide.