An ion reaction device, comprising: an ion injection inlet for receiving a plurality of ions and an ion ejection outlet through which ions can exit the device, a plurality of non-linear rods (L1, L2, L3, L4, L5, L6, L7, L8) disposed relative to one another so as to provide an axial region configured to receive a plurality of anions and cations via said ion injection inlet, and a plurality of trapping regions (18, 20) in communication with the axial region in which said anions and cations can be confined, the plurality of non-linear rods defining a pair of quadrupole rod sets, wherein said quadrupole rod sets are stacked relative to one another so as that each non-linear rod (L1, L2, L3, L4) in one of said quadrupole rod sets is disposed below a respective non-linear rod (L5, L6, L7, L8) of the other of the pair of quadrupole rod sets and in substantial register therewith, wherein each of the non-linear rods includes a longitudinal portion and a transverse portion forming an angle relative to the longitudinal portion, the axial region being spatially defined by the longitudinal portions of the non-linear rods, and wherein the plurality of trapping regions comprise two trapping regions (18, 20) spatially defined by said transverse portion of the non-linear rods, each of said two trapping regions extending from a proximal opening (18a, 20a) in communication with said axial region to a distal opening (18b, 20b), and said ion reaction device further comprising a DC voltage source adapted to apply a DC voltage across at least two of said non-linear rods so as to generate a dipolar electric field within at least a portion of said axial region for spatially separating the received anions and cations and guiding said anions into one of said two trapping regions and the cations into the other of said two trapping regions, and first and second lenses (1, 2), wherein one of said lenses is disposed in proximity of said distal opening of one of the two trapping regions and the other one of said lenses is disposed in proximity of said distal opening of the other of the two trapping regions, said lenses being adapted for application of DC bias voltages thereto for facilitating trapping of the anions and cations in the respective two trapping regions. an ion injection inlet for receiving a plurality of ions and an ion ejection outlet through which ions can exit the device, a plurality of non-linear rods (L1, L2, L3, L4, L5, L6, L7, L8) disposed relative to one another so as to provide an axial region configured to receive a plurality of anions and cations via said ion injection inlet, and a plurality of trapping regions (18, 20) in communication with the axial region in which said anions and cations can be confined, the plurality of non-linear rods defining a pair of quadrupole rod sets, wherein said quadrupole rod sets are stacked relative to one another so as that each non-linear rod (L1, L2, L3, L4) in one of said quadrupole rod sets is disposed below a respective non-linear rod (L5, L6, L7, L8) of the other of the pair of quadrupole rod sets and in substantial register therewith, wherein each of the non-linear rods includes a longitudinal portion and a transverse portion forming an angle relative to the longitudinal portion, the axial region being spatially defined by the longitudinal portions of the non-linear rods, and wherein the plurality of trapping regions comprise two trapping regions (18, 20) spatially defined by said transverse portion of the non-linear rods, each of said two trapping regions extending from a proximal opening (18a, 20a) in communication with said axial region to a distal opening (18b, 20b), and said ion reaction device further comprising a DC voltage source adapted to apply a DC voltage across at least two of said non-linear rods so as to generate a dipolar electric field within at least a portion of said axial region for spatially separating the received anions and cations and guiding said anions into one of said two trapping regions and the cations into the other of said two trapping regions, and first and second lenses (1, 2), wherein one of said lenses is disposed in proximity of said distal opening of one of the two trapping regions and the other one of said lenses is disposed in proximity of said distal opening of the other of the two trapping regions, said lenses being adapted for application of DC bias voltages thereto for facilitating trapping of the anions and cations in the respective two trapping regions.