Ion Mobility Method and Apparatus

Abstract

A method and system for performing an ion mobility based analysis that ionizes the components of a sample into ions; provides a field asymmetric waveform ion mobility or differential mobility spectrometry ion mobility based filter that comprises at least two electrodes, the at least two electrodes being spaced apart such that a constant sized gap is formed there between, through which a drift gas flows; introducing said ions into the drift gas, wherein said drift gas also comprises a mixture of liquid modifiers.

1 . A method of performing an ion mobility based analysis comprising
 ionizing the components of a sample into ions;   providing a field asymmetric waveform ion mobility or differential mobility spectrometry ion mobility based filter that comprises at least two electrodes, the at least two electrodes being spaced apart such that a constant sized gap is formed there between, through which a drift gas flows;   introducing said ions into the drift gas, wherein said drift gas also comprises a mixture of liquid modifiers, said mixture comprising:   a first solvent to improve the separation capability of said drift gas;   a second solvent to suppress either proton transfer or analyte dissociation of said ions, said second solvent having a higher proton solvation energy than that of the first solvent, and being added in excess to that of said first solvent; and   detecting the ions after they have passed through the drift gas.   
     
     
         2 . The method of  claim 1  wherein said first solvent is selected to cluster with the ions. 
     
     
         3 . The method of  claim 2  wherein said first solvent is selected from a group consisting of C1-C10 alcohols, nitrile solvents, halogenated solvents and non-alcohol hydrocarbon based solvents. 
     
     
         4 . The method of  claim 3  wherein said first solvent is hexanol and optionally said second solvent is methanol. 
     
     
         5 . The method of  claim 1  wherein said second solvent is selected from a group consisting of C1-C10 alcohols, nitrile solvents, halogenated solvents and non-alcohol hydrocarbon based solvents. 
     
     
         6 . The method of  claim 1  wherein said mixture further comprises a third solvent that is an arcing suppressant modifier which accepts electrons. 
     
     
         7 . The method of  claim 6  wherein said arcing suppressant modifier is non-polar. 
     
     
         8 . The method of  claim 6  wherein said arcing suppressant modifier is chloroform. 
     
     
         9 . The method of  claim 1  wherein the sample comprises a protein, a peptide, an amino acid, or a mixture thereof. 
     
     
         10 . The method of  claim 1  wherein the sample is comprised of small molecules. 
     
     
         11 . The method of  claim 1  wherein said second solvent is added at least 2 times in excess of said first solvent. 
     
     
         12 . The method of  claim 1  wherein said second solvent is added at least 6 times in excess of said first solvent. 
     
     
         13 . An ion mobility analysis system comprising:
 a differential ion mobility or field asymmetric waveform based filter having at least two electrodes spaced apart from one another to form a constant sized gap there between,   a drift gas supply for introducing a drift gas into the ion mobility based filter;   a liquid modifier supply for introducing a liquid modifier into the drift gas, the liquid modifier supply comprising at least two different liquid solvents; and   an ion detector;   wherein the two different liquid solvents comprise a first solvent to improve the separation capability of said drift gas and a second solvent to suppress either proton transfer or analyte dissociation, said second solvent having a higher proton solvation energy than that of the first solvent, and being present in excess to that of said first solvent when said liquid modifier enters said drift gas supply.   
     
     
         14 . The system of  claim 13  wherein the liquid modifier comprises a third solvent wherein said third solvent is an arcing suppressant modifier. 
     
     
         15 . The system of  claim 13  wherein said first solvent is hexanol and said second solvent is methanol. 
     
     
         16 . The system of  claim 14  wherein said arcing suppressant modifier is chloroform. 
     
     
         17 - 19 . (canceled) 
     
     
         20 . A method of improving the selectivity in a differential mobility or field asymmetric waveform ion mobility analysis system, said method comprising administering an arcing suppressant modifier into said differential mobility or field asymmetric waveform ion mobility analysis system as part of a drift gas, said arcing suppressant modifier being a modifier that scavenges electrons and allows the system to operate at a higher separation voltage than is possible without the use of said arcing suppressant modifier. 
     
     
         21 . The method of  claim 20  wherein said arcing suppressant modifier is chloroform.