Main two purpose
- Carrying the applied current
- Fix the pH at which the electrophoresis is done
Determine
- Electrical charge on solute
- Determines electrode for migration
- Ionization extent of solute
Ionic strength of buffers
- µ = 0.5 Σcizi2
- C= ion conc in mol/L
- Z= charge on ion
- High ionic strength causes high current flow but excessive heat dissipation
- This is used in high-resolution electrophoresis maintaining the system temp
For the separation of serum proteins, the barbital or tris-boric acid-EDTA buffers remain the most popular.
A relatively high ionic strength buffer (µ = 0.075, pH 8.6) containing calcium lactate has been used in high-resolution electrophoresis to improve the separation of serum proteins into as many as 13 bands, with two or more bands in the alpha1, alpha2, and beta globulin regions and one or more additional bands seen in various pathological conditions. Because of higher conductivity and the associated heat produced, it is necessary to reduce the temperature of the system to 10°C to 14°C. Submarine techniques, in which gels are submersed in circulating buffer cooled by an external cooling device or a Peltier plate built into the electrophoresis chamber itself, provide exact temperature control. Effective cooling with less precise temperature control may also be achieved using chambers designed with a sealed compartment of cooled
ethylene glycol, which is in contact with the gel during running.
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