High performance capillary electrophoresis - T.E.A.M.

Modes
Type Result Comment
Extremes of pH ● Reduce coulombic ● pH range from 2 to 12
interactions by
● EOF nearly eliminated at
eliminating wall low pH
and solute charge ● EOF very fast at high pH
differences
● May denature protein
● Can decrease peak
capacity by decreasing
charge differences
High buffer ionic ● Reduce coulombic ● Decreases EOF
strength/ interactions ● Often limited by Joule
concentration
heating
Hydrophilic polymers ● Mask wall charge ● Increases viscosity
(Alkyl celluloses, and reduce EOF ● Can separate by size if
polyvinyl alcohol,
used at high concentradextrans,
tions (CGE)
polyacrylamide)
Surfactants ● Deactivate capillary ● Wide variety of surfactants
Anionic (SDS) surface through ● Easy to use
hydrophobic and/
● MEKC above CMC
Cationic (CTAB) or ionic interaction ● Can decrease or reverse
EOF
Non-ionic (BRIS)
● May irreversibly denature
protein
Zwitterionic (CHAPS)
● Can be used in conjunction
with reversed phase
(see table 14)
LC surface
Table 13
Dynamic deactivation methods
Quaternary amines ● Decrease or ● Also act as ion-pairing
reverse EOF
reagents
3.1.3 Applications of CZE
Many of the applications of CZE have been in the bioscience
area, specifically for peptides and proteins. One example,
in addition to those presented earlier in this chapter, is
glycoprotein separations. Glycoproteins are typically
58