The selectivity in MEKC of pseudo-stationary phases based on polyelectrolyte complexes: I. Composition of the complex.

Polyelectrolyte-surfactant complexes (PSC) of polycarboxylic acids with alkyl-trimethylammonium salts look very promising as a new type of pseudo-stationary phase in micellar electrokinetic chromatography. PSC produce an intramolecular micellar phase, and the morphology of the micelles is significantly different from that of the corresponding "typical" surfactant micelles. Pseudo-stationary phases based on PSC have unique selectivity. In this paper, the effect of the composition (phi) of the PSC of polyacrylic acid (PAA) M(W) 130,000 with dodecyltrimethylammonium bromide (DTAB) and of the PSC of PAA M(W) 450,000 with DTAB on the separation of DNS-amino acids and phenol derivatives in these systems was investigated. Relative retention and relative selectivity were used to describe the electrophoretic behavior of the amino acids and phenol derivatives. The main advantage of PSC pseudo-phases is that the nature and the structure of micelle-like units, and hence the selectivity of electrophoretic separation, could easily be modified by changing the composition of the complex.