Schematic mechanism of separation is shown in Fig. 2. The process
is as follows. At first, the capillary is filled with BGS, and a long
sample plug is injected by gravity into the capillary (Fig. 2A). Then
a high voltage is applied. The analytes migrate rapidly toward the
anode and stack on the boundary between BGS and sample zones
(Fig. 2B). Meanwhile, BGS containing micelles is introduced into
the capillary from the inlet end due to the presence of electroosmotic
flow (EOF). Because the electrophoretic mobility of charged
micelles at the front boundary of sample plug was opposite to
and lower than that of EOF. Therefore, the micelles traverse the
sample plug and sweep the analytes at the behind boundary of
the sample plug (Fang et al., 2014) (Fig. 2C). Subsequently, ENRO
and CIP were separated according to the micellar electrokinetic
capillary chromatography (MEKC) mode (Fig. 2D)