Micellar Electrokinetic Chromatography35
The type of electrophoresis we have been discussing so far is called capillary zone electrophoresis.
Separation is based on differences in electrophoretic mobility. If the capillary
wall is negative, electroosmotic flow is toward the cathode (Figure 26-20) and the order of
elution is cations before neutrals before anions. If the capillary wall charge is reversed by
coating it with a cationic surfactant (Figure 26-24) and the instrument polarity is reversed,
then the order of elution is anions before neutrals before cations. Neither scheme separates
neutral molecules from one another.