The term "electrophoresis" was first used by Michaelis in 1909, to -
scribe the migration of colloids in an electric field. The first
practical elect- phoresis method was described by Tiselius in 1937. He
used a U-tube filled with buffer layered on top of sample; migration
could be monitored using Schlieren optics. In zone electrophoresis, the
U-tube was replaced by paper, a support material employed simply to
prevent or minimize diffusion of ions, so that ions applied in a narrow
strip to the paper will separate and remain as relatively discrete
zones. Paper was superceded by a variety of other media, - cluding
cellulose acetate, hydrolyzed starch (starch gel), agarose, and
polyacry- mide. The latter, in addition to being a support medium, has
size-sieving properties. From the basic zone electrophoresis, other
means of separation have been dev- oped. These include, isoelectric
focusing, isotachophoresis, density gradient el- trophoresis, and
various forms of immunoelectrophoresis. In some ways Capillary
Electrophoresis (CE) has gone full circle back to the original method of
Tiselius. In its simplest form, separations occur in a buffer solution
within a glass (fused silica) tube and detection occurs as sample moves
past an optical window. CE has rapidly developed into a technique that
rivals HPLC in its versatility. All the classical electrophoretic
separations-zone, IEF, and isotachophoresis-have their counterparts in
CE. Excitingly so, and - thoritatively treated in Clinical Applications
of Capillary Electrophoresis.
