Solute-solvent interactions in micellar electrokinetic chromatography: V. Factors that produce peak splitting

Abstract

The experimental conditions that produce analyte peak splitting in micellar electrokinetic capillary chromatography (MEKC) have been systematically investigated. The system studied was a neutral phosphate buffer and sodium dodecyl sulfate (SDS) micelles as pseudostationary phase. A number of analytes showing a wide variety of hydrophobicity values and several organic solvents as sample diluents have been tested. Peak splitting phenomena are mainly due to the presence of organic solvent in the sample solution. They increase with the hydrophobicity of the analyte and decrease with the increase of the surfactant concentration. When hydrophobic compounds are analyzed the suggested ways to avoid split peaks are: (i) the use of 1-propanol or 1-butanol as sample diluent instead of methanol or acetonitrile or (ii) the use of high concentration of surfactant in the separating solution when the analyte must be dissolved in pure methanol or acetonitrile.

Characterization of the Solvation Properties of Sodium n-Dodecyl Sulfate Micelles in Buffered and Unbuffered Aqueous Phases by Solvatochromic Indicators

“…Separation of neutral analytes in micellar electrokinetic chromatography (MEKC) depends on the analyte partition between the aqueous and micellar phases, which in turn depends on the interactions of the analytes with the two solvent phases. 1 In previous works [2][3][4][5][6][7] we have studied the solute-solvent interactions that influence the distribution of analytes between MEKC phases by means of the Abraham's solvation parameter model. The solvation properties of several single and mixed MEKC systems have been characterized.…”

Elimination of the artefact peaks in capillary electrophoresis determination of glutamate by using organic solvents in sample preparation

“…In a subsequent work, they expanded the studies for amphoteric compounds . The phenomenon was also described for organic acids , salt‐containing samples and even MEKC . The defocusing of zones differs from the peak splitting promoted by complex formation between the species and the BGE components .…”

Determination of oregonin in Alnus plants and biological samples by capillary electrophoresis

“…High percentage of organic solvents in sample matrix in MEKC system will result in low plate number or peak splitting [13][14][15]. Water was therefore selected as sample matrix to enhance peak efficiency.…”