Correlation of the intercept and slope of the retention equation ln k' = ln k'w - SC in MECC with the solvatochromic parameters of solutes.
The intercept (ln k'w) and slope (S) of the retention equation in k' = ln k'w - SC in micellar electrokinetic capillary chromatography (MECC) have been studied through linear solvation energy relationships (LSER). It has been observed that the ln k'w is dependent on the properties of micelle and solute but independent of the properties of organic modifier, while the slope (S) is related to the organic modifier and the solute. The LSER results show that the ln k'w of solute is primarily determined by its molecular size and hydrogen bond acceptor (HBA) basicity, whereas the S of solute is primarily determined by its properties in terms of the type of organic modifier, of which molecular size is the most important factor. Additionally, the LSER results show that the interactions of micelle-water and water-organic modifier are also important factors for the retention of solute.