Buffers for electrophoresis and use thereof

Abstract

Various embodiments provide, for example, buffer compositions and/or sieving formulations useful in connection with electrophoresis instruments, such as capillary electrophoresis (CE) devices. In various embodiments, a buffer composition can include Bis-Tris, TAPS and/or TAPSO, and, optionally, a chelating agent, such as EDTA. Methods of separating samples containing bio-molecules, such as DNA or RNA, are also described.

1 . A composition for electrophoresis of nucleic acids, the buffer comprising: 
 (i) TAPS, TAPSO, or Asparagine;    (ii) a compound of the formula: [HO(CH 2 ) m ] 3 C—N[(CH 2 ) n —-OH] 2 ; wherein: m is an integer of from 1 to 3, and n is an integer of form 1 to 4; and    (iii) a metal-chelating agent.    
     
     
         2 . The composition of  claim 1 , wherein said metal-chelating agent is EDTA.  
     
     
         3 . The composition of  claim 1 , wherein the composition is substantially detergent-free.  
     
     
         4 . The composition of  claim 1 , having a pH greater than 7.  
     
     
         5 . The composition of  claim 1  comprising TAPS and Bis-Tris.  
     
     
         6 . The composition of  claim 5 , wherein said metal-chelating agent includes EDTA.  
     
     
         7 . The composition of  claim 5 , wherein the composition is substantially detergent-free.  
     
     
         8 . The composition of  claim 5 , wherein Bis-Tris is present at a concentration of 50-200 mM, wherein TAPS is present at a same concentration as Bis-Tris, and wherein the EDTA is present at 1-2 mM.  
     
     
         9 . The composition of  claim 5 , wherein the Bis-Tris is present at a concentration of 50 mM and the EDTA is present at a concentration of 2 mM.  
     
     
         10 . The composition of  claim 5 , having a pH no less than 7.  
     
     
         11 . The composition of  claim 1 , further comprising an organic polymer.  
     
     
         12 . The composition of  claim 11 , wherein the organic polymer comprises a sieving component comprising a non-crosslinked acrylamide polymer, and a surface interaction component comprising one or more non-crosslinked polymers selected from the group consisting of N,N-disubstituted polyacrylamide, N-substituted polyacrylamide, N-monosubstituted polyacrylamides, polymethacrylamide, polyvinylpyrrolidone, and poly(N,N-dimethylacrylamide).  
     
     
         13 . The composition of  claim 11 , wherein the sieving component comprises one or more polymer selected from the group consisting of linear polyacrylamide, branched acrylamide polymers, and star-shaped acrylamide polymers.  
     
     
         14 . An apparatus for resolving samples, comprising: 
 an electrophoretic channel extending and communicating between anodic and cathodic buffer chambers; and    a buffer, wherein said buffer comprises Bis-Tris, one or both of TAPS and TAPSO, and a metal-chelating agent.    
     
     
         15 . The apparatus of  claim 14 , wherein the channel is defined by a capillary tube.  
     
     
         16 . The apparatus of  claim 14 , wherein the Bis-Tris is contained in said anodic and cathodic buffer chambers and in said channel.  
     
     
         17 . The apparatus of  claim 15 , further comprising a sieving medium held in said channel.  
     
     
         18 . The apparatus of  claim 17 , wherein the electrophoretic channel is configured for capillary electrophoresis.  
     
     
         19 . A method of electrophoresis of nucleic acids, comprising: 
 (a) adding a buffer into an electrophoretic channel, wherein said buffer comprises TAPS, a metal-chelating agent, and a compound of the formula:      (HO(CH 2 )M) 3 C—N[(CH 2 ) n —OH] 2 ,    wherein m is an integer of from 1 to 3, and n is an integer of from 1 to 4;    (b) adding a sample including nucleic acids to be analyzed into said electrophoretic channel; and    (c) applying an electromotive potential across the electrophoretic channel.    
     
     
         20 . The method of  claim 19 , wherein the channel is defined by a capillary tube.  
     
     
         21 . The method of  claim 20 , wherein during the application of the electromotive potential, the buffer has a pH of no less than 7.5.