Page 80 - Academic Press Encyclopedia of Physical Science and Technology 3rd Analytical Chemistry

P1: LDK Revised Pages
Encyclopedia of Physical Science and Technology EN002E-79 May 17, 2001 20:28

366 Capillary Zone Electrophoresis

FIGURE 7 Separation of SDS–protein complexes by polymer-sieving CE. Separation was obtained in an uncoated
capillary using a commercial polymer-sieving applications kit developed for analysis of SDS–protein complexes (Bio-
Rad Laboratories; Hercules, CA).

A. Capillary Gel Electrophoresis is the ability to closely control the porosity by changing
the ratio of monomer to cross-linker. Polyacrylamide gel-
Polyacrylamide gels can be cast within a capillary using
filled capillaries are incompatible with absorbance detec-
the same chemistry employed for casting conventional
tion at short UV wavelengths. Capillary gel electrophore-
polyacrylamide gels. However, preparation and use of
sis (CGE) has been used for high resolution of synthetic
gel-filled capillaries is complicated by bubble formation
antisense nucleotides such as phosphothioate nucleotides.
caused by volume changes during polymerization, and by
extrusion of the gel from the capillary. To circumvent this,
gels are covalently attached to the capillary wall and poly-
B. Replaceable Polymer Solutions
merized in a segmental fashion. Care must be exercised
in their use to avoid bubble formation and contamina- Sieving separations can be accomplished using solu-
tion of the gel bed. An advantage of gel-filled capillaries tions of linear or branched hydrophilic polymers. These