Mc. Breadmore et al., Peak shapes in open tubular ion-exchange capillary electrochromatography of inorganic anions, J CHROMAT A, 892(1-2), 2000, pp. 303-313
An experimental study of parameters influencing peak shapes in ion-exchange
open tubular (OT) capillary electrochromatography (CEC) was conducted usin
g adsorbed quaternary aminated latex particles as the stationary phase. The
combination of separation mechanisms from both capillary electrophoresis a
nd ion-exchange chromatography results in peak broadening in OT-CEC arising
from both these techniques. The sources of peak broadening that were consi
dered included the relative electrophoretic mobilities of the eluent co-ion
and analyte, and resistance to mass transfer in both the mobile and statio
nary phases. The parameters investigated were the mobility of the eluent co
-ion, column diameter, separation temperature and secondary interactions be
tween the analyte and the stationary phase. The electromigration dispersion
was found to influence peak shapes to a minor extent, indicating that chro
matographic retention was the dominant source of dispersion. Improving the
resistance to mass transfer in the mobile phase by decreasing the capillary
diameter improved peak shapes, with symmetrical peaks being obtained in a
25 mu m I.D. column. However, an increase in temperature from 25 degrees C
to 55 degrees C failed to show any significant improvement. The addition of
p-cyanophenol to the mobile phase to suppress secondary interactions with
the stationary phase did not result in the expected improvement in efficien
cy. (C) 2000 Elsevier Science B.V. All rights reserved.