Buffers for electrophoresis and use thereof
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 having a structure of Formula I, wherein:
[HO(CH 2 ) m ] 3 C—N[(CH 2 ) n —OH] 2 Formula I
wherein m is an integer of from 1 to 3, and n is an integer of from 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 the compound of Formula I.
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 the compound of Formula I is present at a concentration of 50-200 mM, wherein TAPS is present at a same concentration as the compound of Formula I, and wherein the EDTA is present at 1-2 mM.
9. The composition of claim 5 , wherein the compound of Formula I 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 5 , wherein the compound of Formula I has the structure wherein m is 1 and n is 2.
12. The composition of claim 1 , further comprising one or more organic polymers.
13. The composition of claim 12 , wherein the one or more organic polymers comprise 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,Ndimethylacrylamide).
14. The composition of claim 12 , wherein the one or more organic polymers comprise a sieving component comprising one or more polymers selected from the group consisting of linear polyacrylamide, branched acrylamide polymers, and star-shaped acrylamide polymers.
15. The composition of claim 12 , wherein the one or more organic polymers comprise one or more uncharged and uncrosslinked water-soluble silica adsorbing polymers.
16. 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:
a) a compound having a structure of Formula I, wherein:
[HO(CH 2 ) m ] 3 C—N[(CH 2 ) n —OH] 2 Formula I
m is an integer of from 1 to 3, and n is an integer of from 1 to 4;
b) one or both of TAPS and TAPSO; and
c) a metal-chelating agent.
17. The apparatus of claim 16 , wherein the channel is defined by a capillary tube.
18. The apparatus of claim 16 , wherein the compound of Formula I is contained in said anodic and cathodic buffer chambers and in said channel.
19. The apparatus of claim 16 , further comprising a sieving medium held in said channel.
20. The apparatus of claim 16 , wherein the electrophoretic channel contains a surface interaction component comprising one or more uncharged and uncrosslinked water-soluble silica adsorbing polymers.
21. A method of electrophoresis of nucleic acids, comprising:
(a) adding a buffer into an electrophoretic channel, wherein said buffer comprises:
i) TAPS;
ii) a metal-chelating agent; and
iii) a compound having a structure of Formula I, wherein:
[HO(CH 2 ) m ] 3 C—N[(CH 2 ) n —OH] 2 Formula I
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.
22. The method of claim 21 , wherein the channel is defined by a capillary tube.
23. The method of claim 22 , wherein during the application of the electromotive potential, the buffer has a pH of no less than 7.5.
24. The method of claim 21 , wherein the electrophoretic channel contains a sieving medium comprising one or organic polymers.
25. The method of claim 24 , wherein the one or more organic polymers comprise 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,Ndimethylacrylamide).
26. The method of claim 24 , wherein the one or more organic polymers comprise one or more polymers selected from the group consisting of linear polyacrylamide, branched acrylamide polymers, and star-shaped acrylamide polymers.
27. The method of claim 21 , wherein the electrophoretic channel contains a surface interaction component comprising one or more uncharged and uncrosslinked water-soluble silica adsorbing polymers.