C. Desiderio et al., SYSTEM PEAKS IN CAPILLARY ZONE ELECTROPHORESIS .2. EXPERIMENTAL-STUDYOF VACANCY PEAKS, Journal of chromatography, 772(1-2), 1997, pp. 81-89
Citations number
9
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
An uncoated capillary with selected background electrolytes (BGEs) was
used to study the migrating vacancies of UV-absorbing components of t
he buffer. Picric and salicylic acids were chosen as the UV-absorbing
anionic species, to be used either as samples in normal capillary elec
trophoresis (CE) mode (direct CE) or as BGE components (reverse CE). T
o study the effect of BGE composition, 2-morpholinoethanesulfonic acid
and monochloroacetate, with lower and higher mobilities, respectively
, were selected as two different BGE co-ions of picrate and salicylate
. In normal CE mode, anionic species provided tailing or fronting peak
s (representing fronting or tailing migrating zones), depending on whe
ther their effective mobilities were lower or higher than the mobility
of the BGE co-ion, respectively. In reverse CE, the effect was the op
posite. Picrate and salicylate vacancies were represented by fronting
or tailing dips (migrating as tailing or fronting zones) when their mo
bilities were higher or lower than that of the BGE co-ion, respectivel
y. The electroosmotic peak may be negative or positive, according to t
he original value of the Kohlrausch regulating function of the sample.
Finally, the difference between migrating vacancies and indirect dete
ction is demonstrated and explained, showing indirect detection of a m
ixture of potassium and sodium acetate detected simultaneously with a
benzoic acid vacancy.