Separation of very hydrophobic analytes by micellar electrokinetic chromatography. III. Characterization and optimization of the composition of the separation electrolyte using carbon number equivalents

Abstract

Four coefficients are suggested to characterize the separation properties of separation electrolytes in MEKC. These coefficients are the electrophoretic mobility of the pseudostationary phase (PSP), the electroosmotic mobility, and two parameters which can be obtained via the Martin equation using the retention data of the members of a suitable homologous series. These four coefficients are used for the characterization of separation electrolytes applicable to the separation of very hydrophobic analytes (log P(OW) = 3-4) with SDS as PSP and to quantitatively describe the influence of the buffer additives ACN and urea for the fine-tuning of retention factors and the additive calcium chloride for the fine-tuning of the width of the migration time window. Together with carbon number equivalents (N*(C)) as analyte descriptors the suggested coefficients provide a tool for the fast optimization of the composition of the separation electrolyte. The proposed method optimization scheme is applied to the separation of ingredients of essential oils. Predicted resolutions are compared to experimental results.

Analytical Separation of Carcinogenic and Genotoxic Alkenylbenzenes in Foods and Related Products (2010–2020)

“…MEKC is the suitable CE mode for alkenylbenzenes separation because these analytes are electrically neutral (see Figure 1). Indeed in 2008, Huhn, et al [66] utilized the principle of MEKC to separate the hydrophobic neutral alkenylbenzenes eugenol, safrole, methyleugenol and myristicin. The separation media consisted of 60 mM sodium dodecyl sulphate (SDS) in 7.5 mM sodium borate (pH 9).…”

Marker compounds for the determination of retention factors in EKC

“…Several publications deal with the iteration procedure for the determination of t ps values to further characterize the pseudostationary phases 91, 106, 118. The concept is based on the results of the regression analysis, which yields two parameters a and b, the intercept and the slope of the Martin equation, i.e.…”

High Performance Liquid Chromatography versus Stacking-Micellar Electrokinetic Chromatography for the Determination of Potentially Toxic Alkenylbenzenes in Food Flavouring Ingredients

“…An alternative analytical separation technique to HPLC for alkenylbenzenes is micellar electrokinetic chromatography (MEKC) [ 34 , 35 ], which is a mode of capillary electrophoresis. Huhn and co-workers employed MEKC with negatively charged sodium dodecyl sulfate (SDS) micelles to separate the electrically neutral eugenol, safrole, methyleugenol, and myristicin in sassafras essential oil samples [ 36 ]. In MEKC, the micelles that were formed from SDS above the critical micelle concentration (CMC) acted as the chromatographic pseudophase.…”