Method of cooling a multiplexed capillary electrophoresis system

Abstract

A multiplexed capillary electrophoresis system with cooling sufficient to prevent overheating during chiral separation. The system includes a thermally insulated enclosure enclosing a bundle of capillary tubes, a light source and photodetector. A heat transfer system is provided for cooling closely spaced portions and spread apart portions of the capillary tubes to an extent sufficient to prevent overheating of the tubes and contents thereof due to the heat generated during chiral separation.

What is claimed is:  
     
         1 . A multiplexed capillary electrophoresis system with cooling sufficient to prevent overheating during chiral separation, said system comprising: 
 a bundle of capillary tubes having inlet end portions spaced apart for loading of fluid samples to be analyzed into the tubes, outlet end portions for exit of said fluid samples from the tubes, and intermediate portions between the inlet and outlet end portions arranged in a generally planar array in which the intermediate portions extend side-by-side in closely spaced generally parallel relation,    a power source for applying a potential difference between the inlet end portions and the outlet end portions to cause an electrical current to flow through the contents of the capillary tubes at a level sufficient to cause chiral separation in said fluid samples, said current generating heat in the tubes and the contents thereof,    a light source for directing light to pass through said array of intermediate portions of the capillary tubes,    a photodetector for receiving light passing through said array,    a thermally insulated enclosure enclosing said bundle of capillary tubes, light source and photodetector,    a first heat transfer mechanism for cooling said array of closely spaced intermediate portions of the capillary tubes, and    a second heat transfer mechanism for cooling at least the spaced apart inlet end portions of the capillary tubes.    
     
     
         2 . A multiplexed capillary electrophoresis system as set forth in  claim 1  wherein said first heat transfer mechanism comprises a conduction heat transfer mechanism.  
     
     
         3 . A multiplexed capillary electrophoresis system as set forth in  claim 2  wherein said array of intermediate portions of the capillary tubes has a width, said conduction heat transfer mechanism comprising a body of thermally conductive material having a length, a width, a cooling face adapted to extend across substantially the entire width of the bundle for cooling the capillaries of the bundle, and a window in the body for exposing said array.  
     
     
         4 . A multiplexed capillary electrophoresis system as set forth in  claim 3  wherein said conduction heat transfer mechanism further comprises passaging in the body for the flow of a coolant through the body to cool the body, said passaging having an inlet adapted for connection to a source of coolant and an outlet.  
     
     
         5 . A multiplexed capillary electrophoresis system as set forth in  claim 3  wherein said body has a recess therein extending the length of the body for receiving said array, said cooling face defining one side of said recess.  
     
     
         6 . A multiplexed capillary electrophoresis system as set forth in  claim 5  wherein said body comprises a front cooling slab having a front face and a rear face constituting said cooling face, and a back slab removably attached to said front cooling slab, said back slab having a front face in contact with the rear face of the front cooling slab and a rear face.  
     
     
         7 . A multiplexed capillary electrophoresis system as set forth in  claim 6  wherein the front face of the back slab has a shallow channel formed therein defining the remaining sides of the recess in the body.  
     
     
         8 . A multiplexed capillary electrophoresis system as set forth in  claim 7  wherein said window comprises aligned openings in said front and back slabs.  
     
     
         9 . A multiplexed capillary electrophoresis system as set forth in  claim 3  wherein said body is of metal and said cooling face has a dielectric thermally conductive coating thereon engageable by said capillary tubes.  
     
     
         10 . A multiplexed capillary electrophoresis system as set forth in  claim 3  further comprising a refrigeration system for controlling the temperature of said body.  
     
     
         11 . A multiplexed capillary electrophoresis system as set forth in  claim 3  further comprising a dielectric coating on said cooling face.  
     
     
         12 . A multiplexed capillary electrophoresis system as set forth in  claim 2  wherein said second heat transfer mechanism comprises a convective heat transfer mechanism.  
     
     
         13 . A multiplexed capillary electrophoresis system as set forth in  claim 12  wherein said convective heat transfer mechanism comprises a heat exchange device having a cooling surface, and a fan for circulating air over said cooling surface and said inlet end portions of the capillary tubes.  
     
     
         14 . A multiplexed capillary electrophoresis system as set forth in  claim 13  wherein said heat exchange device and said fan are located in said enclosure.  
     
     
         15 . A multiplexed capillary electrophoresis system as set forth in  claim 14  wherein said heat exchange device and said fan are operable to maintain the air temperature inside the enclosure in the range of 0-90 degrees C.  
     
     
         16 . A multiplexed capillary electrophoresis system as set forth in  claim 15  wherein said heat exchange device and said fan are operable to maintain the air temperature inside the enclosure at about 10 degrees C.  
     
     
         17 . A method of preventing overheating of a bundle of capillary tubes during a multiplexed capillary electrophoresis process for substantially concurrently effecting chiral separation in multiple fluid samples, said method comprising: 
 mounting a bundle of capillary tubes in an enclosure so that inlet end portions of the tubes are spaced apart for loading of said fluid samples into the tubes and intermediate portions of the tubes are arranged in an array in which the intermediate portions extend side-by-side in closely spaced generally parallel relation,    loading said fluid samples into the inlet end portions of the tubes,    causing an electrical current to flow through the contents of the capillary tubes at a level sufficient to cause chiral separation in said fluid samples, said current generating heat in the tubes and contents thereof,    analyzing one or more properties of the fluid samples as they flow through the array of intermediate portions of the capillary tubes;    cooling the array of closely spaced intermediate portions of the capillary tubes by using a first heat transfer mechanism, and    cooling at least the spaced apart inlet end portions of the capillary tubes by using a second heat transfer mechanism.    
     
     
         18 . A method as set forth in  claim 17  wherein said array is cooled by conduction heat transfer.  
     
     
         19 . A method as set forth in  claim 17  wherein said inlet end portions are cooled by convection heat transfer.  
     
     
         20 . A method as set forth in  claim 19  wherein said array is cooled by conduction heat transfer.  
     
     
         21 . A method as set forth in  claim 17  further comprising maintaining the air temperature inside the enclosure in the range of 0-90 degrees C. during said chiral separation.  
     
     
         22 . A method as set forth in  claim 21  further comprising maintaining said air temperature inside the enclosure at about 10 degrees C.  
     
     
         23 . A method of substantially concurrently effecting chiral separation in multiple fluid samples using a multiplexed capillary electrophoresis process, said method comprising: 
 mounting a bundle of capillary tubes so that inlet end portions of the tubes are positioned for loading of said fluid samples into the tubes and intermediate portions of the tubes are arranged in an array in which the intermediate portions extend side-by-side in closely spaced generally parallel relation,    loading said fluid samples into the inlet end portions of the tubes,    causing an electrical current to flow through the contents of the capillary tubes at a level sufficient to cause chiral separation in said fluid samples during said electrophoresis process, and    analyzing one or more properties of the fluid samples as they flow through the array of intermediate portions of the capillary tubes after chiral separation has been achieved.    
     
     
         24 . A method as set forth in  claim 23  further comprising cooling said bundle of capillary tubes and the contents thereof during said chiral separation to prevent overheating, said cooling step comprising 
 cooling the array of closely spaced intermediate portions of the capillary tubes by using a first heat transfer mechanism, and  
 cooling spaced apart inlet end portions of the capillary tubes by using a second heat transfer mechanism.  
 
     
     
         25 . A method as set forth in  claim 24  wherein said array is cooled by conduction heat transfer.  
     
     
         26 . A method as set forth in  claim 24  wherein said inlet end portions are cooled by convection heat transfer.  
     
     
         27 . A method as set forth in  claim 26  wherein said array is cooled by conduction heat transfer.  
     
     
         28 . A method as set forth in  claim 24  wherein said cooling step further comprises enclosing said bundle of capillary tubes in an enclosure, and maintaining the air temperature inside the enclosure in the range of 0-90 degrees C. during said chiral separation.  
     
     
         29 . A method as set forth in  claim 28  further comprising maintaining said air temperature inside the enclosure at about 10 degrees C.  
     
     
         30 . A multiplexed capillary electrophoresis system for chiral separation, said system comprising: 
 a bundle of capillary tubes having inlet end portions positioned for loading of fluid samples to be analyzed into the tubes, outlet end portions for exit of said samples from the tubes, and intermediate portions between the inlet and outlet end portions arranged in an array in which the intermediate portions extend side-by-side in closely spaced generally parallel relation,    a power source for applying a potential difference between the inlet end portions and the outlet end portions to cause an electrical current to flow through the contents of the capillary tubes at a level sufficient to cause chiral separation in said fluid samples,    a light source for directing light to pass through said array of intermediate portions of the capillary tubes, and    a photodetector for receiving light passing through said array.    
     
     
         31 . A multiplexed capillary electrophoresis system as set forth in  claim 30  further comprising a thermally insulated enclosure enclosing said bundle of capillary tubes, light source and photodetector, and a heat transfer system for cooling said array and said inlet end portions of the capillary tubes to an extent sufficient to prevent overheating of the tubes and contents thereof due to heat generated during chiral separation.  
     
     
         32 . A multiplexed capillary electrophoresis system as set forth in  claim 31  wherein said heat transfer system comprises a first heat transfer mechanism for cooling said array of closely spaced intermediate portions of the capillary tubes, and a second heat transfer mechanism for cooling at least the inlet end portions of the capillary tubes.  
     
     
         33 . A multiplexed capillary electrophoresis system as set forth in  claim 32  wherein said first heat transfer mechanism comprises a conduction heat transfer mechanism and said second heat transfer mechanism comprises a convective heat transfer mechanism.