Apparatus and method for adjustment of ion separation resolution in FAIMS

A method for separating ions, comprising:

• providing a FAIMS analyzer region having a first ion inlet for introducing ions thereto and having an ion outlet for extracting a subset of the ions that is selectively transmitted along an average ion flow path through the FAIMS analyzer region;
• introducing ions into the FAIMS analyzer region via the first ion inlet;
• selectively transmitting a subset of the ions through the FAIMS analyzer region along a first length of an average ion flow path;
• changing an average ion flow path length through the FAIMS analyzer region;
• and,
• transmitting ions along the second length of an average ion flow path.

A method for separating ions, comprising:

• providing a FAIMS analyzer region having an ion inlet end for receiving ions and having an ion outlet for providing a subset of the ions that is selectively transmitted between the ion inlet end and the ion outlet of the FAIMS analyzer region;
• defining a first average ion flow path length through the FAIMS analyzer region;
• defining a second average ion flow path length through the FAIMS analyzer region, the second average ion flow path length different than the first average ion flow path length;
• and,
• controllably switchably providing ions along the first average ion flow path length and the second average ion flow path length.