FAIMS with non-destructive detection of selectively transmitted ions

Abstract

Disclosed is a high field asymmetric waveform ion mobility spectrometer (FAIMS) with optical based detection of selectively transmitted ions. Light from a light source is directed through an optical port in an electrode of the FAIMS. A light detector is provided for receiving light that is one of transmitted and scattered by the selectively transmitted ions within the FAIMS.

1 . An apparatus for separating ions in the gas phase, comprising: 
 a high field asymmetric waveform ion mobility spectrometer comprising two electrodes defining an analyzer region therebetween, the two electrodes disposed in a spaced apart arrangement for allowing ions to propagate therebetween and for providing an electric field within the analyzer region resulting from the application of an asymmetric waveform voltage to at least one of the two electrodes and from the application of a compensation voltage to at least one of the two electrodes, for selectively transmitting a first ion type in the analyzer region at a given combination of asymmetric waveform voltage and compensation voltage; and,    a probe signal generator for generating a probe signal which when applied to the selectively transmitted ions results in light including information relating to the selectively transmitted ions within the analyzer region.    
   
   
       2 . An apparatus according to  claim 1 , wherein the probe signal generator comprises an electrical controller that is in electrical communication with at least one of the two electrodes for applying the asymmetric waveform voltage to the at least one of the two electrodes.  
   
   
       3 . An apparatus according to  claim 2 , comprising an optical port disposed adjacent to the analyzer region for propagating the light including information relating to the selectively transmitted ions therethrough.  
   
   
       4 . An apparatus according to  claim 3 , comprising a light detector in optical communication with the optical port for detecting light including information relating to the selectively transmitted ions.  
   
   
       5 . An apparatus according to  claim 4 , wherein the light detector is in the form of an infrared light detector.  
   
   
       6 . An apparatus according to  claim 1 , wherein the probe signal generator comprises a light source in optical communication with a portion of the analyzer region, for launching incident light having a wavelength within a predetermined range of wavelengths toward the selectively transmitted ions within the analyzer region.  
   
   
       7 . An apparatus according to  claim 6 , wherein the analyzer region includes an inlet orifice and an outlet orifice for introducing a gas flow between the two electrodes and, 
 wherein, in use, at least one of the asymmetric waveform voltage, the compensation voltage and the gas flow are adjustable within the analyzer region, so as to confine some of the selectively transmitted ions within a 3-dimensional region of space within the analyzer region.    
   
   
       8 . An apparatus according to  claim 7 , comprising an optical port disposed within a surface of one of the first and second electrodes for propagating the incident light between the light source and the 3-dimensional region of space within the analyzer region.  
   
   
       9 . An apparatus according to  claim 8 , wherein the light source is in the form of an infrared light source for providing incident light within the infrared portion of the electromagnetic spectrum.  
   
   
       10 . An apparatus according to  claim 8 , wherein the light source is in the form of a laser light source.  
   
   
       11 . An apparatus according to  claim 6 , wherein the two electrodes comprise outer and inner generally cylindrical coaxially aligned electrodes defining a generally annular space therebetween, the annular space forming the analyzer region.  
   
   
       12 . An apparatus according to  claim 11 , wherein the analyzer region includes an inlet orifice and an outlet orifice for introducing a gas flow between the outer and inner generally cylindrical coaxially aligned electrodes, and wherein, in use, at least one of the asymmetric waveform voltage, the compensation voltage and the gas flow are adjustable within the analyzer region, so as to confine some of the selectively transmitted ions within a 3-dimensional region of space within the analyzer region.  
   
   
       13 . An apparatus according to  claim 11 , comprising an optical port disposed within a surface of one of the inner and outer generally cylindrical electrodes for transmitting the incident light between the light source and the 3-dimensional region of space within the analyzer region.  
   
   
       14 . An apparatus according to  claim 13 , wherein the optical port is disposed within a surface of the outer generally cylindrical electrode at a point along the length of the outer generally cylindrical electrode that is approximately aligned with the 3-dimensional region of space within the analyzer region.  
   
   
       15 . An apparatus according to  claim 13 , wherein the inner generally cylindrical electrode includes a curved surface terminus that is shaped for directing the selectively transmitted ions generally radially inwardly around the terminus so as to increase the ion density of the selectively transmitted ions within the 3-dimensional region of space relative to the ion density of the selectively transmitted ions within an adjacent portion of the analyzer region, the 3-dimensional region of space being disposed intermediate the terminus of the inner electrode and an ion outlet orifice of the analyzer region.  
   
   
       16 . An apparatus according to  claim 15 , including a channel through the inner generally cylindrical electrode and open at both ends, the channel forming an opening at the center of the curved surface terminus that is approximately aligned with the 3-dimensional region of space.  
   
   
       17 . An apparatus according to  claim 16 , wherein the optical port is disposed within the opening at the center of the curved terminus.  
   
   
       18 . An apparatus according to  claim 1 , wherein the probe signal generator is for supporting a non-destructive analysis of the selectively transmitted first ion type within the analyzer region.  
   
   
       19 . An apparatus for separating ions in the gas phase, comprising: 
 a high field asymmetric waveform ion mobility spectrometer comprising two electrodes defining an analyzer region therebetween, the two electrodes disposed in a spaced apart arrangement for allowing a gas flow to pass therebetween and for providing an electric field within the analyzer region resulting from the application of an asymmetric waveform voltage to at least one of the two electrodes and from the application of a compensation voltage to at least one of the two electrodes, for selectively transmitting a first ion type in the analyzer region at a given combination of asymmetric waveform voltage and compensation voltage, whereby, in use, the asymmetric waveform voltage, the compensation voltage and the gas flow are adjustable, so as to confine some of the selectively transmitted ions within a 3-dimensional region of space within the analyzer region;    a first optical port disposed within a surface of one of the two electrodes and adjacent to a portion of the analyzer region including the 3-dimensional region of space; and,    a light source disposed external to the analyzer region and in optical communication with the first optical port for providing incident light having a wavelength within a predetermined range of wavelengths to the selectively transmitted ions within the 3-dimensional region of space.    
   
   
       20 . An apparatus according to  claim 19 , comprising a second optical port disposed within a surface of one of the two electrodes and adjacent to the portion of the analyzer region including the 3-dimensional region of space, the second optical port for propagating other light resulting from the passage of the incident light through the 3-dimensional region of space therethrough.  
   
   
       21 - 38 . (canceled)