Resolution assessment and performance of several organic modifiers in hybrid micellar liquid chromatography

The performance of four criteria that measure the elementary resolution (mo dified selectivity, modified Rs, peak purity, and orthogonal valley-to-peak ratio) was critically assessed using as global resolution function, the pr oduct of elementary measurements. The peak purities and valley-to-peak crit eria yielded the best description of the overall separation according to th e shape of the resolution surfaces compared to the peak arrangements in the chromatograms, the capability of defining unambiguously the composition re gions of complete resolution, and the resolution achieved in the predicted optimums. Peak purities were used to compare the effect of five organic mod ifiers (1-propanol, 1-butanol, 1-pentanol, acetonitrile and tetrahydrofuran ) on the separation quality of micellar mobile phases of sodium dodecyl sul phate (SDS). Acetonitrile, a common solvent in reversed should read reverse d-phase liquid chromatography but scarcely used in micellar liquid chromato graphy. allowed the most satisfactory resolution in an extensive compositio n region with very small overlapping and sufficiently low retention times. The enhanced resolution was produced by the improved selectivity, and large r efficiencies and asymmetries of the chromatographic peaks. (C) 2001 Elsev ier Science B.V. All rights reserved.