Mass Spectrometer

Abstract

A mass spectrometer is disclosed comprising a first ion trap or ion guide, a single ion mobility spectrometer or separator stage and a second ion trap or ion guide arranged downstream of the ion mobility spectrometer or separator. In a mode of operation ions from the second ion trap or ion guide are passed from the second ion trap or ion guide back upstream to the ion mobility spectrometer or separator.

1 - 71 . (canceled) 
     
     
         72 . A mass spectrometer comprising:
 a first ion trap or ion guide;   a first device for separating ions according to their ion mobility or rate of change of ion mobility with electric field strength; and   a mass analyser;   wherein said first ion trap or ion guide is arranged to pass ions to said device, and wherein said device is arranged so that ions pass through said device multiple times before being passed onwards to said mass analyser.   
     
     
         73 . (canceled) 
     
     
         74 . A mass spectrometer as claimed in  claim 72 , wherein ions are caused to pass through said first device multiple times in a first direction. 
     
     
         75 . A mass spectrometer as claimed in  claim 74 , wherein ions are caused to separate according to their ion mobility or rate of change of ion mobility with electric field strength each time they pass through said first device in said first direction. 
     
     
         76 . A mass spectrometer as claimed in  claim 72 , comprising a control system arranged to vary the number of passes of ions through said first device during a cycle of operation. 
     
     
         77 . A mass spectrometer as claimed in  claim 72 , comprising a voltage source for maintaining an axial DC voltage gradient along an axial length of said first device. 
     
     
         78 . A mass spectrometer as claimed in  claim 77 , comprising a transient DC voltage means arranged and adapted to apply one or more transient DC voltages or one or more transient DC voltage waveforms for urging ions against said axial DC voltage gradient. 
     
     
         79 . A mass spectrometer as claimed in  claim 72 , comprising a second ion trap or ion guide arranged downstream of said first device. 
     
     
         80 . A mass spectrometer as claimed in  claim 72 , comprising an ion fragmentation or reaction region disposed upstream or downstream of said first device and arranged so that ions are passed from said first device to said ion fragmentation or reactive device, and wherein fragment, daughter, product or adduct ions derived from said ions are passed onwards to said first device. 
     
     
         81 . A mass spectrometer comprising:
 a first device for separating ions according to their ion mobility or rate of change of ion mobility with electric field strength; and   one or more ion guiding or ion trapping regions,   wherein said one or more ion guiding or ion trapping regions are arranged to receive ions which emerge from said first device, to pass or transmit at least some of said ions onwards, and to then pass ions from said one or more ion guiding or ion trapping regions to said first device.   
     
     
         82 . A mass spectrometer as claimed in  claim 81 , comprising a first ion trap or ion guide arranged upstream of said first device. 
     
     
         83 . A mass spectrometer as claimed in  claim 81 , comprising a second ion trap or ion guide arranged downstream of said first device. 
     
     
         84 . A mass spectrometer as claimed in  claim 81 , wherein ions are caused to pass through said first device multiple times so that ions undergo multiple separations according to their ion mobility or rate of change of ion mobility with electric field strength. 
     
     
         85 . A mass spectrometer as claimed in  claim 81 , wherein ions are caused to pass through said first device multiple times in a first direction. 
     
     
         86 . A mass spectrometer as claimed in  claim 85 , wherein ions are caused to separate according to their ion mobility or rate of change of ion mobility with electric field strength in said first direction. 
     
     
         87 . A mass spectrometer as claimed in  claim 81 , comprising a control system arranged to vary the number of passes of ions through said first device during a cycle of operation. 
     
     
         88 . A mass spectrometer as claimed in  claim 87 , further comprising a mass analyser, wherein at the end of each cycle of operation, said control system causes ions to be transmitted from said first device or from said one or more ion guiding or ion trapping regions to said mass analyser for subsequent mass analysis. 
     
     
         89 . A mass spectrometer as claimed in  claim 81 , comprising a voltage source for maintaining an axial DC voltage gradient along an axial length of said first device. 
     
     
         90 . A mass spectrometer as claimed in  claim 89 , comprising a transient DC voltage means arranged and adapted to apply one or more transient DC voltages or one or more transient DC voltage waveforms for urging ions against said axial DC voltage gradient. 
     
     
         91 . A mass spectrometer as claimed in  claim 81 , wherein said one or more ion guiding or ion trapping regions comprise an ion fragmentation or reaction device, wherein ions are passed from said first device to said ion fragmentation or reaction device, and wherein fragment, daughter, product or adduct ions derived from said ions are passed onwards to said first device. 
     
     
         92 . A mass spectrometer as claimed in  claim 81 , wherein ions are separated according to their ion mobility in said first device.