Patent ID: 7034289

Claim:
An apparatus for separating ions, comprising: an analyzer region defined by a space between first and second electrodes, the first electrode having a length and at least a quadratic ruled outer surface, the second electrode overlapping the first electrode along a first portion of the length thereof and having at least a quadratic ruled inner surface opposite to the at least a quadratic ruled outer surface of the first electrode; at least a first contact on at least one of the first and second electrodes for receiving a first direct current voltage, and for applying an asymmetric waveform voltage to the at least one of the first and second electrodes; a third electrode aligned with the second electrode for defining a space between the third electrode and the first electrode, the third electrode overlapping the first electrode along a second portion of the length thereof adjacent to the first portion of the length thereof and other than overlapping with the first portion of the length thereof; and, a second contact on the third electrode for at least one of receiving a second direct current voltage and applying the asymmetric waveform voltage to the third electrode, whereby during use the third electrode is maintained at a different potential relative to the second electrode, such that a potential gradient is formed in a direction along the length of the first electrode.