Abstract: A method for analyzing ions includes providing a desolvation chamber in communication with an analytical gap of a FAIMS analyzer, via an ion inlet orifice. A flow of ions is introduced into the desolvation chamber along a flow path that is toward the ion inlet orifice and into the analytical gap of the FAIMS analyzer. A flow of a desolvation gas is provided into the desolvation chamber via a first gas inlet, such that a portion of the flow of the desolvation gas is counter-current to the flow of ions. A flow of a carrier gas is provided separately via a second gas inlet, which is defined downstream relative to the desolvation chamber. In particular, the composition of the carrier gas is different than the composition of the desolvation gas. Accordingly, the flow of the carrier gas is provided substantially into the analytical gap for transporting ions along a path between the ion inlet orifice and an ion outlet orifice of the analytical gap.

Abstract: A combined rf-only/FAIMS apparatus is disclosed for use in mass spectrometry and other applications. The disclosed apparatus includes a plurality of curved electrodes arranged around a central ion transmission channel. FAIMS functionality is removed electronically when not desired by application of radio frequency (rf) waveforms to the curved electrodes.

Abstract: A combined rf-only/FAIMS analyzer is disclosed for use in mass spectrometry and other applications. The disclosed apparatus includes a plurality of flat-plate electrodes arranged around a longitudinal axis of the apparatus so as to define generally a parallelogram in a cross section taken in a plane that is normal to the longitudinal axis. FAIMS is removed electronically when not desired by application of radio frequency (rf) waveforms to the flat-plate electrodes.

Abstract: A FAIMS cell has an elongated inner electrode with a longitudinal axis extending along a first direction. The inner electrode has a curved outer surface that defines a circle when viewed in a cross section that is taken in a plane normal to the longitudinal axis, which itself passes through the center of the circle so defined. An outer electrode having an inner surface is disposed in a spaced-apart facing relationship relative to the outer surface of the inner electrode so as to define an analytical gap therebetween. A first ion inlet orifice is defined through a first portion of the outer electrode, and an ion outlet orifice is defined through a second portion of the outer electrode. In particular, the first ion inlet orifice has a first ion injection axis that does not pass through the center of the circle. Furthermore, the second electrode does not have defined through any portion thereof an ion inlet orifice having an ion injection axis that passes through the center of the circle.

Abstract: A FAIMS cell including one of side-to-side cylindrical geometry electrodes and stacked-plate electrodes is adapted with a medial surface feature for focusing ions along a lateral direction within an ion separation region of the FAIMS cell. The medial surface feature is provided as one of a recessed channel within an electrode surface and a protruding ridge extending from an electrode surface. The medial surface feature is aligned with a defined aggregate direction of ion travel within the ion separation region for focusing ions along the lateral direction in opposition to the tendency of ions to spread out as a result of space charge repulsion, ion-ion repulsive forces, diffusion and gas flows. The electrical field and fluid dynamic effects produced by the medial surface feature beneficially affect ion transmission efficiency through the FAIMS cell.

Abstract: An ion spectrometer apparatus is disclosed having an ion source, an ion mobility spectrometer device such as a FAIMS cell, and a capillary for transporting ions from the ion source to the entrance of the FAIMS cell. The capillary is heated to promote evaporation of solvent from incompletely desolvated droplets entering the capillary inlet, thereby preventing or minimizing operational problems associated with the presence of wet material in the FAIMS cell. The FAIMS cell may be used to selectively transmit ions to a mass analyzer.

Abstract: A FAIMS cell including one of side-to-side cylindrical geometry electrodes and stacked-plate electrodes is adapted with a medial surface feature for focusing ions along a lateral direction within an ion separation region of the FAIMS cell. The medial surface feature is provided as one of a recessed channel within an electrode surface and a protruding ridge extending from an electrode surface. The medial surface feature is aligned with a defined aggregate direction of ion travel within the ion separation region for focusing ions along the lateral direction in opposition to the tendency of ions to spread out as a result of space charge repulsion, ion-ion repulsive forces, diffusion and gas flows. The electrical field and fluid dynamic effects produced by the medial surface feature beneficially affect ion transmission efficiency through the FAIMS cell.