Electric field control in ion mobility spectrometry

Claim 2

Apparatus for detecting ions comprising, an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17); second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a drift region (20) having a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region substantially parallel to said longitudinal axis (55) to move said ions toward a collector (22) at first times, for generating an electric field in said drift region (20) substantially parallel to said longitudinal axis (55) to move said ions away from said collector (22) at second times, and for generating an electric field in said drift region (20) substantially parallel to said longitudinal axis (55) to move said ions toward said collector (22) at third times.

Claim 3

The apparatus of Claim 1 wherein said second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) includes generating an electric field in said reaction region (17) during said first and second times to move second ions of a first polarity toward a shutter (18) for holding said second ions, further characterized by said shutter (18) including means (37, 38, 39, 60, 62) for releasing said second ions of first polarity into said drift region (20) at the beginning of third times to join with other ions in said drift region (20).

Claim 4

Apparatus for detecting ions comprising: an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a first end of a drift region (20) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) substantially parallel to said longitudinal axis (55), said electric field at first times having a first direction at said first end to accept ions from said reaction region (17), and a transition region between said first and second ends where said electric field reverses direction with respect to said first direction to provide an ion well for holding ions, said electric field in said drift region (20) at second times having said first direction from said first end to said second end to move said ions toward a collector.

Claim 5

Apparatus for detecting ions comprising: an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a first end of a drift region (20) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) substantially parallel to said longitudinal axis (55), said electric field at first times having a first direction at said first end to accept ions from said reaction region (17), and a transition region between said first and second ends where said electric field reverses direction with respect to said first direction to provide an ion well for holding ions, said electric field in said drift region (20) at second times having said first direction from said first end to said second end to move said ions toward a collector.

Claim 6

The apparatus of Claim 3 further characterized by said third means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) including at third times prior to said second times fourth means (62, 60, 39, 50-54, 40-44) for increasing the magnitude of the electric field in said transition region to compress said ions within a shorter distance along said longitudinal axis (55) in said transition region.

Claim 7

Apparatus for detecting ions comprising, an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17). first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a first end of a drift region (20) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) substantially parallel to said longitudinal axis (55) wherein the magnitude of said electric field is a function of longitudinal distance from said first end of said drift region (20).

Claim 8

Apparatus for detecting ions comprising, an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17). first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a first end of a drift region (20) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) substantially parallel to said longitudinal axis (55) wherein the magnitude of said electric field is a function of longitudinal distance from said first end of said drift region (20).

Claim 9

Apparatus for identification of ionized molecules having a similar mobility (K₀) but having dissimilar atomic mass unit (AMU) and fracturing energy levels comprising: an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a first end of a drift region (20) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region (20) substantially parallel to said longitudinal axis (55) to isolate and position said ionized molecules having a similar mobility in said drift region (20), fourth means (62, 60, 39, 50-54, 40-44) for fracturing a portion of said ionized molecules to form daughter ions as a function of fracturing energy, said third means (62, 60, 39, 50-54, 40-44) including fifth means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region substantially parallel to said longitudinal axis (55) to reposition and move said ionized molecules and daughter ions toward a collector (22) positioned at said second end of said drift region (20).

Claim 10

Apparatus for identification of ionized molecules having a similar mobility (K₀) but having dissimilar atomic mass unit (AMU) and fracturing energy levels comprising: an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction region (17) to move said ions toward a first end of a drift region (20) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region (20) substantially parallel to said longitudinal axis (55) to isolate and position said ionized molecules having a similar mobility in said drift region (20), fourth means (62, 60, 39, 50-54, 40-44) for fracturing a portion of said ionized molecules to form daughter ions as a function of fracturing energy, said third means (62, 60, 39, 50-54, 40-44) including fifth means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region substantially parallel to said longitudinal axis (55) to reposition and move said ionized molecules and daughter ions toward a collector (22) positioned at said second end of said drift region (20).

Claim 11

Apparatus for chemically reacting selected ions of predetermined mobility comprising: an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating positive and negative ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction (17) to move ions of a first polarity at first times and ions of a second polarity at second times toward a first end of a drift region (17) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region (20) substantially parallel to said longitudinal axis (55) to isolate and position ions of said first polarity having a predetermined mobility in said drift region (20) at a first predetermined distance from said first end, said third means (62, 60, 39, 50-54, 40-44) including fourth means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region (20) at distances less than said first predetermined distance from said first end substantially parallel to said longitudinal axis (55) to isolate and position ions of said second polarity having a predetermined mobility at a second predetermined distance from said first end, said third means (62, 60, 39, 50-54, 40-44) including fifth means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) to move said ions of first polarity and said ions of second polarity toward each other whereby they chemically combine.

Claim 12

Apparatus for chemically reacting selected ions of predetermined mobility comprising: an inlet (16) for introducing a carrier gas (25) and a sample gas (29) into a reaction region (17), first means (33) for generating positive and negative ions from said carrier gas (25) and sample gas (29) in said reaction region (17), second means (30, 34, 32, 36, 60, 62) for generating an electric field in said reaction (17) to move ions of a first polarity at first times and ions of a second polarity at second times toward a first end of a drift region (17) having a second end and a longitudinal axis (55), characterized by third means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region (20) substantially parallel to said longitudinal axis (55) to isolate and position ions of said first polarity having a predetermined mobility in said drift region (20) at a first predetermined distance from said first end, said third means (62, 60, 39, 50-54, 40-44) including fourth means (62, 60, 39, 50-54, 40-44) for generating a sequence of electric fields at predetermined times in said drift region (20) at distances less than said first predetermined distance from said first end substantially parallel to said longitudinal axis (55) to isolate and position ions of said second polarity having a predetermined mobility at a second predetermined distance from said first end, said third means (62, 60, 39, 50-54, 40-44) including fifth means (62, 60, 39, 50-54, 40-44) for generating an electric field in said drift region (20) to move said ions of first polarity and said ions of second polarity toward each other whereby they chemically combine.

Claim 19

The method of Claim 10 wherein said step of fracturing includes applying an electric field having a first polarity and a second polarity as a function of distance along said longitudinal axis (55) at first times and a reversed polarity at second times.