Electrophoretic mass spectrometry probes and systems and uses thereof

Abstract

The invention generally relates to electrophoretic mass spectrometry probes and systems and methods of uses thereof. In certain aspects, the invention provides a mass spectrometry probe having a hollow body with a distal tip, an electrically conductive hollow conduit, and an electrode. The electrically conductive hollow conduit may be operably coupled to a reservoir and a power source, and the electrically conductive hollow conduit may be configured to transport a liquid sample into the hollow body and polarize the liquid sample as it flows through the electrically conductive hollow conduit and into in the hollow body. The electrode and the electrically conductive hollow conduit are disposed within the hollow body (e.g., at different heights within the hollow body).

What is claimed is: 
     
         1 . A mass spectrometry probe comprising:
 a hollow body comprising a distal tip;   an electrically conductive hollow conduit configured to be operably coupled to a sample reservoir and a power source, wherein the hollow conduit is configured to transport a liquid sample from the reservoir and into the hollow body and polarize the liquid sample as the liquid sample flows through the hollow conduit and into the hollow body; and   an electrode, wherein the electrode and the hollow conduit are disposed within the hollow body.   
     
     
         2 . The mass spectrometry probe according to  claim 1 , further comprising the power source and the reservoir, wherein both the electrically conductive hollow conduit and the electrode are coupled to the power source. 
     
     
         3 . The mass spectrometry probe according to  claim 1 , wherein the mass spectrometry probe is a nanospray probe. 
     
     
         4 . The mass spectrometry probe according to  claim 3 , wherein the hollow body of the nanospray probe is a hollow capillary. 
     
     
         5 . The mass spectrometry probe according to  claim 1 , further comprising a liquid sample disposed within the hollow body. 
     
     
         6 . The mass spectrometry probe according to  claim 5 , wherein a distal end of the hollow conduit is positioned within the liquid sample ejected from the hollow conduit into the hollow body and the electrode is positioned at a proximal location in the hollow body such that there is an air gap between the electrode and the liquid sample within the hollow body. 
     
     
         7 . The mass spectrometry probe according to  claim 6 , wherein the electrode and the electrically conductive hollow conduit subject the liquid sample to an inductive charge. 
     
     
         8 . A system comprising:
 a mass spectrometry probe comprising: a hollow body comprising a distal tip; a power source; a reservoir; an electrically conductive hollow conduit operably coupled to the reservoir and the power source, wherein the hollow conduit is configured to transport a liquid sample into the hollow body and polarize the liquid sample as the liquid sample flows through the hollow conduit and into the hollow body; and an electrode, wherein the electrode and the hollow conduit are disposed within the hollow body; and   a mass spectrometer.   
     
     
         9 . The system according to  claim 8 , wherein the mass spectrometry probe is a nanospray probe. 
     
     
         10 . The system according to  claim 9 , wherein the hollow body of the nanospray probe is a hollow capillary. 
     
     
         11 . The system spectrometry probe according to  claim 8 , wherein the hollow body is a unitary hollow body. 
     
     
         12 . The system according to  claim 8 , further comprising a liquid disposed within the hollow body. 
     
     
         13 . The system according to  claim 12 , wherein a distal end of the hollow conduit is positioned within the liquid sample ejected from the hollow conduit into the hollow body and the electrode is positioned at a proximal location in the hollow body such that there is an air gap between the electrode and the liquid sample within the hollow body. 
     
     
         14 . The system according to  claim 13 , wherein the electrode and the electrically conductive hollow conduit subject the liquid sample to an inductive charge. 
     
     
         15 . The system according to  claim 8 , wherein mass spectrometer is a miniature mass spectrometer. 
     
     
         16 . A method for analyzing a sample, the method comprising:
 providing a mass spectrometry probe comprising: a hollow body comprising a distal tip; an electrically conductive hollow conduit operably coupled to a reservoir and a power source, wherein the hollow conduit is configured to transport a liquid sample into the hollow body and polarize the liquid sample as the liquid sample flows through the hollow conduit and into in the hollow body; and an electrode, wherein the electrode and the hollow conduit are disposed within the hollow body;   introducing a liquid sample comprising a target analyte and a plurality of liquid-phase ions from the reservoir and into the hollow body via the hollow conduit;   applying a voltage to the hollow conduit while transporting the liquid sample from the reservoir through the hollow conduit and into the hollow body and inductively applying voltage from the electrode to the liquid sample, thereby causing the plurality of liquid-phase ions to separate from the target analyte;   terminating the voltage from the electrode while maintaining the voltage to the hollow conduit to thereby cause the target analyte to be emitted from the distal tip and become ionized; and   analyzing the ionized target analyte in a mass spectrometer.   
     
     
         17 . The method according to  claim 16 , further comprising introducing a liquid into the hollow body prior to introducing the liquid sample to the hollow body. 
     
     
         18 . The method according to  claim 16 , wherein applying voltage from the electrode causes the plurality of liquid-phase ions to migrate toward the electrode. 
     
     
         19 . The method according to  claim 16 , wherein prior to the applying step, the method further comprises applying voltage only to the hollow conduit. 
     
     
         20 . The method according to  claim 16 , wherein the liquid sample is a biological sample.