Electrokinetic separations with micellar solutions and open-tubular capillaries

Abstract

in the spectrum of lasalocid, which is assigned to ( -+ Na)Na+. With monensin spotted on a TLC plate, the sensitivity of detection was established as well below 0.1 µg.A major concern was the possible interference related to the components in the TLC adsorbent and the masking tape. However, no background interference was observed in the mass range of interest based on blank tests of both fluorescent and nonfluorescent TLC plates and direct tests of the masking tape. Also, contamination of the ion source by the TLC adsorbent, i.e., silica gel, was not observed. However, after the depletion of the FAB matrix liquid, the flake of adsorbent from plastic-backed TLC sheets appeared to remain intact while that from glass TLC plates tended to disintegrate. For this reason we favor the Use of plastic-backed TLC sheets.In conclusion, we have demonstrated a simple and rapid method for directly obtaining FAB spectra of TLC fractions which circumvents the problems associated with the previously cited methods. ACKNOWLEDGMENTWe wish to thank D. B. Borders and . T. Lee of Lederle Laboratories, American Cyanamid Company, for providing the coccidiostats and the TLC separation procedure.LITERATURE CITED(1) Deverse, F.

A comparison of ionic liquids to molecular organic solvents as additives for chiral separations in micellar electrokinetic chromatography

“…Elution orders were determined by spiking a single pure S-(-) enantiomer into the solution of the corresponding racemic analytes. The equations for the calculation of resolution (R s ) and RSD were obtained from references [32,33]. At least three measurements were made for each experimental condition for which RSD values were calculated.…”

Ultrasonic acoustic wave detection of single or capillary electrophoretically resolved underivatized amino acids

“…The particular mode for separating neutral compounds or compounds with similar charge-to-size ratio is MECC, which was developed by Terabe et al 4 The selection of surfactants is important in the CE separation because the surfactant molecules, if charged, will lead to an increase in the capillary current. SDS, which is an ionic surfactant, indeed causes an additional current when a high voltage is applied for CE separation.…”

Use of affinity capillary electrophoresis for characterizing pharmaceutical colloidal vehicle systems thermodynamically

“…The capacity factor, k 0 of uncharged solutes was calculated from the observed migration times using the following equation [33,34]:…”

“…In ACE and MEEKC the capacity factor k 0 is directly related to the partition coefficients between the aqueous and micellar phases as [31,33]: where P mw is the partition coefficient of the solute between the micellar phase and the aqueous phase, Q is the phase ratio and V mc and V aq are the volumes of the micelle and the remaining aqueous phase. Therefore, we can calculate the partition coefficients from the migration factor according to Equation (3):…”