Probes with hydrophobic coatings for gas phase ion spectrometers

Abstract

This invention provides a mass spectrometry probe including a substrate having a surface and a film that coats the surface. The film includes openings that define features for the presentation of an analyte. The film also has a lower surface tension that the surface tension of the substrate surface, and has a water contact angle between 120° and 180°.

What is claimed is:  
     
         1 . A probe that is removably insertable into a gas phase ion detector comprising: 
 a) a substrate having a surface adapted to present an analyte to an ionization source and    b) a film that coats the surface, wherein the film: 
 i) comprises at least one opening that exposes the surface, thereby defining a feature for applying a liquid comprising an analyte;  
 ii) has a water contact angle of between 120° and 180°; and  
 iii) has less surface tension than the substrate-surface,  
   whereby a liquid applied to the feature is sequestered in the feature.    
     
     
         2 . The probe of  claim 1  wherein the film comprises a perfluorinated hydrocarbon, halogenated hydrocarbon, aliphatic hydrocarbon, aromatic hydrocarbon, polysilane, organosilane or combinations thereof.  
     
     
         3 . The probe of  claim 1  wherein the film comprises a perfluorinated hydrocarbon.  
     
     
         4 . The probe of  claim 1  wherein the film comprises a plurality of openings arranged in a regular array.  
     
     
         5 . The probe of  claim 1  wherein the film is electrically conductive.  
     
     
         6 . The probe of  claim 2  wherein the substrate surface comprises metal.  
     
     
         7 . The probe of  claim 2  wherein an adsorbent comprising a binding functionality is attached to the feature.  
     
     
         8 . A system comprising: 
 a) a gas phase ion detector comprising an inlet port; and    b) a probe of  claim 1  inserted into the inlet port.    
     
     
         9 . The system of  claim 8  wherein the gas phase ion detector is a mass spectrometer.  
     
     
         10 . The system of  claim 9  wherein the mass spectrometer is a laser desorption mass spectrometer.  
     
     
         11 . A method of detecting an analyte comprising: 
 a) placing the analyte on a feature of a surface of a probe of claim;    b) inserting the probe into an inlet port of a gas phase ion detector comprising: 
 i) an ionization source that desorbs the analyte from the probe surface into a gas phase and ionizes the analyte; and  
 ii) an ion detector in communication with the probe surface that detects desorbed ions;  
   c) desorbing and ionizing the analyte with the ionization source; and    d) detecting the ionized analyte with the ion detector.    
     
     
         12 . The method of  claim 11  wherein the gas phase ion detector is a mass spectrometer.  
     
     
         13 . The method of  claim 12  wherein the mass spectrometer is a laser desorption mass spectrometer.