Kz. Cheng et al., SEPARATION OF METAL-CATIONS BY ELECTROPHORESIS IN A POSITIVELY CHARGED COATED CAPILLARY, Journal of chromatography, 706(1-2), 1995, pp. 517-526
In the expanding field of capillary electrophoresis, the use of coated
capillaries is becoming more widespread. Application of a thin polyme
r coating on the surface of the silica capillary wall makes it possibl
e to generate a capillary wall of positive or no charge when using a t
ypical buffer of a pH of 5.0 to ca. 6.0, thereby altering the electroo
smotic flow. Indeed, when a coating is used which carries a positive c
harge under appropriate buffer conditions, the electroosmotic flow is
reversed from the normal direction. This reversal increases the migrat
ion times of metal cations and also improves separation efficiency. In
this work, a positively charged coated capillary was used with a 2-am
inopyridine buffer system for the separation of metal cations. Separat
ions using this system compared favorably with other published results
. The positively charged coated column yielded cation separations supe
rior to those obtained with uncoated columns. This system proved effec
tive for the separation of many cations, including lanthanides.