sodium-dodecyl-sulfate and 2-2-bis(4-glycidyloxyphenyl)propane

Retention index (I), rather than retention factor (k), was found to be a more reasonable parameter for comparison of the relative affinity of disubstituted benzenes in MEEKC and MEKC, due to independent of I with the SDS surfactant concentration. MEKC and MEEKC may give similar or different I values, depending on types of moieties. With known I and K(ow) for alkylbenzenes as references in MEKC and MEEKC, the values of K(ow) for disubstituted benzenes can be estimated from the observed I values, where K(ow) is the octanol-water distribution constant. In addition, a group additive approach can be used to predict I for disubstituted benzenes with different moieties from the average observed I for the disubstituted benzenes with same moieties. However, electronic effects and/or intramolecular interaction may result in the different observed I from prediction.

Topics: Benzene Derivatives; Benzhydryl Compounds; Chromatography, Micellar Electrokinetic Capillary; Curcumin; Epoxy Compounds; Linear Models; Octanols; Sodium Dodecyl Sulfate; Water

The resolution (R(s)) of hydrophobic analytes in microemulsion EKC (MEEKC) and MEKC with suppressed electroosmosis was investigated using bisphenol-A-diglycidyl ether and its derivatives (BADGEs) as test analytes. Separation scales were compared using our equation for the resolution, R(s)= (square rootN/4)(alpha-1)/(1+K(2)),where k is the retention factor, alpha the selectivity (alpha = k(2)/k(1) for k(2) > or = k(1)>0), and N the average efficiency. At given concentrations of SDS and organic cosolvent in the buffer, in comparison with MEKC, MEEKC was found to provide better resolution of BADGEs, mainly due to the significantly smaller k in MEEKC, but not the greater alpha in MEEKC, while a comparable range of N. Significantly improved resolution of BADGEs was obtained with increase in the concentration of organic cosolvent in the MEEKC and MEKC buffers, while small change in R(s) with the SDS concentration in a range of 100-180 mM. In addition, a decrease in temperature or voltage resulted in slightly better R(s).

Topics: Algorithms; Benzhydryl Compounds; Buffers; Chromatography, Micellar Electrokinetic Capillary; Electroosmosis; Electrophoresis, Capillary; Emulsions; Epoxy Compounds; Micelles; Organic Chemicals; Sensitivity and Specificity; Sodium Dodecyl Sulfate; Solvents; Temperature