Methods and apparatus for improving the sensitivity of capillary zone electrophoresis

Abstract

The present invention relates to novel methods and apparatus for improving the sensitivity of capillary zone electrophoresis (CZE). The invention particularly concerns devices comprising a channel that contains an in-line sol-gel column to concentrate samples being subjected to capillary zone electrophoresis, and the use of such devices to enhance the sensitivity of capillary zone electrophoresis.

1 . A sol-gel concentrating device comprising a channel containing a column of a monolith of a polymerized alkylsilicate gel matrix containing chromatographic sorbent particles, wherein said gel matrix is polymerized under conditions sufficient to permit evaporation of solvent without substantial destabilization of said monolith.  
     
     
         2 . The sol-gel concentrating device of  claim 1 , wherein said channel of said device is a capillary tube, and is bounded by porous frits, and wherein said column of said device is polymerized within said capillary tube.  
     
     
         3 . The sol-gel concentrating device of  claim 1 , wherein said alkylsilicate gel matrix is a tetraethylorthosilicate gel matrix.  
     
     
         4 . The sol-gel concentrating device of  claim 1 , wherein said chromatographic sorbent particles are octadecylsilica particles.  
     
     
         5 . The sol-gel concentrating device of  claim 1 , wherein said sol-gel is polymerized via step-wise, multistep incubation.  
     
     
         6 . The sol-gel concentrating device of  claim 5 , wherein said step-wise, multistep incubation comprises heating under conditions suitable to promote the polymerization of the monolith without causing significant evaporation of solvent, followed by incubation under conditions sufficient to promote the evaporation of solvent from the polymerized monolith, followed by incubation under conditions sufficient to cure the alkylsilicate gel matrix.  
     
     
         7 . The sol-gel concentrating device of  claim 1 , wherein said device is employed in an analytical or preparative process to promote the concentrating of an analyte of a sample.  
     
     
         8 . The sol-gel concentrating device of  claim 7 , wherein said analytical or preparative process is selected from the group consisting of liquid chromatography, capillary zone electrophoresis, capillary electrophoresis, capillary electrochromatography (CEC), reverse phase chromatography, ion-exchange chromatography, affinity chromatography and normal phase chromatography.  
     
     
         9 . The sol-gel concentrating device of  claim 7 , wherein said analytical or preparative process is selected from the group consisting of an immunoassay and an enzymatic reaction.  
     
     
         10 . The sol-gel concentrating device of  claim 7 , wherein said analyte is selected from the group consisting of: a protein, a peptide, a nucleic acid molecule, a drug, an agricultural compound, a bacteria and a virus.  
     
     
         11 . The sol-gel concentrating device of  claim 1 , wherein said channel of said device is a microchannel of a chip or plate.  
     
     
         12 . A method for concentrating an analyte in a sample being subjected to an analytical or preparative process, wherein said method comprises concentrating said analyte using a sol-gel concentrating device, said device comprising a channel containing a column of a monolith of a polymerized alkylsilicate gel matrix containing chromatographic sorbent particles, wherein said gel matrix is polymerized under conditions sufficient to permit evaporation of solvent without substantial destabilization of said monolith.  
     
     
         13 . The method of  claim 12 , wherein said device is polymerized within a capillary tube, and is bounded by porous frits.  
     
     
         14 . The method of  claim 12 , wherein said alkylsilicate gel matrix is a tetraethylorthosilicate gel matrix.  
     
     
         15 . The method of  claim 12 , wherein said chromatographic sorbent particles are octadecylsilica particles.  
     
     
         16 . The method of  claim 12 , wherein said sol-gel is polymerized via step-wise, multistep incubation.  
     
     
         17 . The method of  claim 16 , wherein said step-wise, multistep incubation comprises heating under conditions suitable to promote the polymerization of the monolith without causing significant evaporation of solvent, followed by incubation under conditions sufficient to promote the evaporation of solvent from the polymerized monolith, followed by incubation under conditions sufficient to cure the alkylsilicate gel matrix.  
     
     
         18 . The method of  claim 12 , wherein said device is employed in an analytical or preparative process to promote the concentrating of an analyte of a sample.  
     
     
         19 . The method of  claim 18 , wherein said analytical or preparative process is selected from the group consisting of liquid chromatography, capillary zone electrophoresis, capillary electrophoresis, capillary electrochromatography (CEC), reverse phase chromatography, ion-exchange chromatography, affinity chromatography and normal phase chromatography.  
     
     
         20 . The method of  claim 18 , wherein said analytical or preparative process is selected from the group consisting of an immunoassay and an enzymatic reaction.  
     
     
         21 . The method of  claim 18 , wherein said analyte is selected from the group consisting of: a protein, a peptide, a nucleic acid molecule, a drug, an agricultural compound, a bacteria and a virus.  
     
     
         22 . The method of  claim 12 , wherein said channel of said device is a microchannel of a chip or plate.