Z. Chen et al., Separation selectivity in micellar electrokinetic chromatography using different anionic surfactants as pseudo-stationary phases, CHROMATOGR, 54(9-10), 2001, pp. 629-633
Micellar electrokinetic chromatography (MEKC) and ligand exchange-MEKC have
been widely used for the separation of achiral and chiral compounds. For t
he separation of different compounds, one expects to obtain the desired dif
ferent separation selectivity by choosing different surfactants as pseudo-s
tationary phases. This paper describes a comparative study on the separatio
n selectivity in MEKC and LE-MEKC using different anionic surfactants such
as sodium dodecyl sulfate (SDS), sodium alkyl polyoxyethylene sulfate (AES-
Na) and sodium alpha -sulfonated fatty acid methyl esters (alpha -SF-Na). D
ifferent selectivities were observed with these anionic surfactants. For th
e separation of aromatic derivatives by MEKC, better selectivity was obtain
ed by using AES-Na than SIDS micellar phases. For the simultaneous separati
on of positional enantiomers of o-, m- and p-fluoro-DL-phenylalanine by LE-
MEKC, the SDS micellar phase provided the best selectivity among these anio
nic surfactants. Furthermore, the critical micelle concentrations (CMC) of
these surfactants were also estimated by LE-MEKC.