Electroelution

 Molecules and particles purified by gel electrophoresis can be recovered from the gel by their electrophoresis into solution, a process termed electroelution . The procedure consists of excising the gel slices of interest, loading them onto a concentrating (stacking) gel, and electrophoresing the material contained in the slice into a recovery cup or dialysis bag attached to the bottom of the stacking gel. If the electroelution employs a single electrophoresis buffer, the sample moves directly into the recovery vessel. Electroelution of the band of interest into the stacking gel of a discontinuous buffer system of disc electrophoresis has the advantage that the material to be eluted is concentrated into a single band visualized by a tracking dye, so its collection can be visually monitored. This type of electroelution is practical with microgram amounts of sample, which can be recovered with a typical yield of 70%. Polymeric impurities in the electroeluate may be removed by gel filtration (1).

 More directly, electroelution can be conducted at a right angle to the direction of migration, with instant monitoring of recovery until it is complete (2). Sequential elution of bands into a buffer chamber flushed continuously or discontinuously (designated “elution-PAGE”) is available for samples of up to milligrams, but it involves dilution of the eluate and the risk of losses in the elution chamber (3).

References

1.N. Y. Nguyen and A. Chrambach (1981) In Gel Electrophoresis of Proteins: A Practical Approach (B. D. Hames and D. Rickwood, eds.), IRL Press, Oxford, pp. 145–155. 

2. E. Gombocz and E. Cortez (1995) Appl. Theor. Electrophoresis 4, 197–209. 

3. A. Chrambach and D. Rodbard (1981) In Gel Electrophoresis of Proteins: A Practical Approach (B. D. Hames and D. Rickwood, eds.), IRL Press, Oxford, pp. 93–143.