Patent ID: 7170053

Claim:
A method for separation and analysis of gas-phase ions, comprising: providing a plurality of electrodes containing a space therebetween, said electrodes carrying voltages establishing an electric field over at least a part of said space, said field comprising a first component along a first (drift) axis superposed over a second substantially stronger component along a second (alignment) axis, said second axis disposed at a defined angle relative to said first axis; filling at least a portion of said space with a buffer gas; periodically introducing into said space a discrete packet of analyte ions comprising at least one species therein having an electric dipole, wherein said second field component substantially aligns said dipole(s) of said at least one species along said second axis, and said first component pulls said substantially aligned ions along the direction of said first axis; and whereby said ions are spatially separated or identified based on a measured collision cross section with gas molecules that is other than averaged equally over all spatial orientations and is direction-specific depending on said defined angle.