Separation mechanism of micellar-electrokinetic capillary chromatography studied by quantitative-structure retention relationship

The retention index in micellar electrokinetic capillary chromatography (MECC) has been analyzed by the quantitative-structure retention relationship. a good linear relationship between the retention index in the SDS surfactant MECC and the logP and logk(w) values has been obtained; however, there is no such a linear relationship of retention index in the CTAB, DTAB surfactant MECC versus logP and logk(w) values. The retention index in the cationic and anionic surfactant MECC can be well correlated with the solvatochromic parameter; of solutes. The molecular size and hydrogen bond interaction of solutes make the most important contributions to the retention index. The former has almost no relation with the surfactant properly, and the latter depends on the property of the surfactant used. Different surfactant MECCs offer different selectivities for the separation of polar compounds.