Separation efficiency of dual-selector systems in capillary electrophoresis

Generalized model of electromigration with 1:1 (analyte:selector) complexation stoichiometry: Part I. Theory

“…Finally, ionic strength may be a serious problem whenever a charged selector is used (either alone or in the mixture). In some cases, appropriate correction can be applied [29,35]. However, ionic strength related effects, particularly in systems containing highly charged big molecules, have not been sufficiently described yet.…”

“…(10) is applicable to virtually an unlimited number of selectors under the assumption (2). It is useful for describing migration of a single analyte under interaction with a commercial mixture of selectors [28] as well as for investigating separation characteristics, such as mobility difference and selectivity, as a function of mixture composition, namely in the dual selector mixtures [29]. The aim of this paper is to show that the dependence of the effective mobility of the analyte on the selector concentration can always be converted to the S A S S formula (4) whenever the various forms of the analyte interact with an arbitrary number of selectors, in 1:1 (analyte:selector) stoichiometry each.…”

Generalized model of electromigration with 1:1 (analyte:selector) complexation stoichiometry: Part II. Application to dual systems and experimental verification

“…It has already been demonstrated that (i) an analyte which is a weak monovalent [15] or divalent [22] acid and interacts with one selector can be treated as if only one free analyte form were present; (ii) a mixture of selectors can analogically be regarded as a single selector [38][39][40]. A constant H 3 O + concentration in the BGE is a prerequisite in the former case and a constant mixture composition is required in the latter case.…”

“…The model of Wren and Rowe [10] results when a single free analyte form interacts with a single selector (here further referred to as S A S S systems). When a single analyte form interacts with multiple selectors, the dualselector model [40] and the multi-selector model [38,39] published by our group are obtained from the M A M S model (1). Finally, when there is only one selector but a monoacidic/monobasic analyte (and the dependence of i0 on [H 3 O + ] is expressed explicitly), the M A M S model results in the model of Williams and Vigh [18].…”

“…Along with their increasing applications in analytical chemistry, theoretical models have been developed describing the electromigration of fully dissociated, neutral, or partly dissociated analytes interacting with one selector [10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Several models dealing with dual-and multi-selector systems have also been published [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] (we recently summarized them in a review [41]). However none of these models takes into account the possible protonation equilibria of the analyte along with its simultaneous interaction with multiple selectors.…”