High performance ion mobility spectrometer apparatus and methods
An ion mobility spectrometry method wherein ions are separated along a drift axis while providing a drift gas flow in a direction that is substantially neither in the direction of the drift axis nor opposite to the drift axis. Ion mobility spectrometer operation methods use a cross-directional gas flow in a drift tube and/or a segmented drift tube for pre-separation.
1. A time-of-flight ion mobility spectrometer method, comprising:
ionizing a sample with at least one component;
pulsing the ionized sample into a drift tube;
separating the components of the ionized sample pulse along a drift axis of the drift tube, and;
providing a cross drift flow substantially in a direction that is greater than zero but less then one hundred and eighty degrees from the drift axis, and
detecting the components that are separated based on their drift times.
2. The spectrometer method of claim 1 , wherein applying the cross drift flow to different segments and/or regions of the drift tube.
3. The spectrometer method of claim 1 , further comprises adding at least one chemical modifier to the cross drift flow.
4. The spectrometer method of claim 3 , wherein applying one chemical modifier to a specific segment and/or region of the drift tube by way of the cross drift flow; and applying a second chemical modifier to a specific segment and/or region of the drift tube by way of the cross drift flow.
5. The spectrometer method of claim 1 , further comprises removing neutral molecules in the drift tube along with the drift flow.
6. The spectrometer method of claim 1 , wherein providing the cross drift flow is combined with a counter or uni-direction flow.
7. The spectrometer method of claim 6 , wherein the counter or uni-direction flow is provided in a segment and/or region of the drift tube and the cross drift flow is provided in another segment and/or region of the drift tube.