The separation of some anthrone-C-glucosyl constituents of aloe was carried
out by isocratic capillary electrochromatography using a 50 mum I. D. colu
mn packed with 3 mum ODS silica gel. In comparison to HPLC mode, CEC resolu
tion of aloins was obtained in a very short time with a high selectivity fa
ctor. The influence of mobile phase parameters (pH and ionic strength of th
e buffer, acetonitrile amount in the eluent etc.) on the retention of aloin
s was examined in order to improve the separation conditions and to study t
he retention mechanism. Efficiency was found to increase with decreasing th
e EOF up to a reduced plate height of about 2 at a reduced linear velocity
of 0.3 mm s(-1). This effect was ascribed to the fact that, under the buffe
r conditions used (pH 8), aloins are partially anionically charged, with a
consequent low mass transfer between the mobile and stationary phases. Howe
ver, resolution remains almost the same in a wide pH range permitting basel
ine separations of aloins in short analysis times. Since aloins are known t
o undergo fast degradation reaction dependent on pH, a kinetic study was al
so carried out. The method was extended to the analysis of aloins in food a
nd cosmetic products.