@article {341,
	title = {Accurately describing weak analyte-additive interactions by capillary electrophoresis},
	journal = {Electrophoresis},
	volume = {23},
	number = {6},
	year = {2002},
	note = {ISI Document Delivery No.: 536KNTimes Cited: 12Cited Reference Count: 33},
	month = {Mar},
	pages = {880-888},
	type = {Article},
	abstract = {When modeling analyte-additive interactions in capillary electrophoresis (CE), it is necessary to correct for all changes in the apparent electrophoretic mobility of an analyte that are not due to specific binding. Current models based on dynamic complexation have corrected for bulk viscosity changes in the background electrolyte (BGE) when additives are used, while assuming negligible changes in the dielectric constant and other physicochemical properties of the solution. In this report, a study of weak interactions between deoxyribonucleotides and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) revealed significant nonideality in binding isotherms. Changes in the dielectric properties of the solution due to the addition of high concentrations of HP-beta-CD to the BGE was observed to alter the electrophoretic mobility of analytes. A relative dielectric correction factor was required to normalize analyte mobilities to a reference state of zero additive concentration. The use of both a relative dielectric factor and a viscosity correction factor was found to increase the accuracy of the model, reflected by a higher degree of correlation between predicted and measured analyte mobilities. This type of correction is particularly relevant when studying weak analyte binding interactions or when using high concentrations of additive in the BGE. This work is vital for accurate determination of weak binding constants and mobility values, as well as providing a deeper understanding of the fundamental parameters influencing a separation in CE.},
	keywords = {analyte-additive interactions, BETA-CYCLODEXTRIN, binding isotherms, capillary electrophoresis, CHIRAL SEPARATION, cyclodextrin, deoxyribonucleotides, DYNAMIC COMPLEXATION, ELECTROKINETIC CHROMATOGRAPHY, ELECTROPHORESIS, ENANTIOMERS, MIGRATION BEHAVIOR, MODEL, OPTIMIZATION, QUANTITATIVE DESCRIPTION, viscosity-dielectric corrections factors, weak, ZONE},
	isbn = {0173-0835},
	url = {<Go to ISI>://000174699400008},
	author = {Britz-McKibbin, P. and Chen, D. D. Y.}
}
@article {397,
	title = {Applications of on-line weak affinity interactions in free solution capillary electrophoresis},
	journal = {Electrophoresis},
	volume = {23},
	number = {6},
	year = {2002},
	note = {ISI Document Delivery No.: 536KNTimes Cited: 26Cited Reference Count: 109},
	month = {Mar},
	pages = {815-822},
	type = {Review},
	abstract = {The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary electrophoresis approach is feasible when the migration of complexed molecules is different from the migration of free molecules and when separation conditions are nondenaturing. In this review, we focus on applying weak interactions as tools to enhance the separation of closely related molecules, e.g., drug enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On-line affinity capillary electrophoresis methods are especially valuable for enantiomeric separations and for functional characterization of the contents of biological samples that are only available in minute quantities.},
	keywords = {affinity capillary electrophoresis, ALPHA(1)-ACID, AMYLOID-P COMPONENT, biomolecular interactions, capillary electrophoresis, CHIRAL SEPARATION, CHROMATOGRAPHY, CONSTANTS, ELECTROKINETIC, enantiomer separation, ENANTIOSELECTIVE PROTEIN, FRONTAL ANALYSIS, GLYCOPROTEIN, isotherms, MEASURE BINDING, PARTIAL-FILLING TECHNIQUE, PROTEIN-BINDING, review, separation methods, ZONE-ELECTROPHORESIS},
	isbn = {0173-0835},
	url = {<Go to ISI>://000174699400002},
	author = {Heegaard, N. H. H. and Nissen, M. H. and Chen, D. D. Y.}
}
@article {4484,
	title = {Monte Carlo simulation of error propagation in the determination of binding constants from rectangular hyperbolae. 2. Effect of the maximum-response range},
	journal = {Journal of Physical Chemistry A},
	volume = {103},
	number = {1},
	year = {1999},
	note = {ISI Document Delivery No.: 174NXTimes Cited: 29Cited Reference Count: 55},
	month = {Jan},
	pages = {197-202},
	type = {Article},
	abstract = {Many processes dictated by chemical equilibria can be described by rectangular hyperbolae. Fitting chemical responses to rectangular hyperbolas also allows the binding constants for these equilibria to be estimated. Unfortunately, the propagation of error through the different methods of estimating the binding constants is not well understood. Monte Carlo simulations are used to assess the accuracy and precision of binding constants estimated using a nonlinear regression method and three linear plotting methods. The effect of the difference between the physical response of the uncomplexed substrate and the response of the substrate-ligand complex (i.e., the maximum-response range) was demonstrated using errors typical for a capillary electrophoresis system. It was shown that binding constant estimates obtained using nonlinear regression were more accurate and more precise than estimates from when the other regression methods were used, especially when the maximum-response range was small. The precision of the nonlinear regression method correlated well with the curvature of the binding isotherm. To obtain a precise estimate for the binding constant, the maximum-response range needed to be much larger (over 70 times larger for the conditions used in this experiment) than the error present in individual data points.},
	keywords = {capillary electrophoresis, CHIRAL SEPARATION, COMPLEXATION MODEL, CONCENTRATION-DEPENDENT TRANSPORT, dynamic, ELIMINATION PROCESSES, MICHAELIS-MENTEN PARAMETERS, MIGRATION BEHAVIOR, QUANTITATIVE DESCRIPTION, THERMODYNAMIC PARAMETERS, TIOCONAZOLE ENANTIOMERS},
	isbn = {1089-5639},
	url = {<Go to ISI>://000079042200026},
	author = {Bowser, M. T. and Chen, D. D. Y.}
}
@article {4208,
	title = {Analyte-additive interactions in nonaqueous capillary electrophoresis: a critical review},
	journal = {Trac-Trends in Analytical Chemistry},
	volume = {17},
	number = {7},
	year = {1998},
	note = {ISI Document Delivery No.: 107HPTimes Cited: 54Cited Reference Count: 40},
	month = {Aug},
	pages = {424-434},
	type = {Review},
	abstract = {This article reviews the recent developments in nonaqueous capillary electrophoresis and discusses the effect of the solvent on analyte-additive interactions. When nonaqueous solvents are used, solvophobic interactions are generally weaker than those in water; therefore, those additives that can change the analyte mobility through electrostatic or donor-acceptor interactions should be further explored. (C) 1998 Elsevier Science B.V. All rights reserved.},
	keywords = {ANIONS, CHIRAL SEPARATION, cohesion energy, density, dielectric constant, electron donor-acceptor interaction, FORMAMIDE, ION, MEDIA, nonaqueous capillary electrophoresis, SEPARATION SELECTIVITY, solvent effect, SOLVENTS, SURFACTANTS, WATER, ZONE ELECTROPHORESIS},
	isbn = {0165-9936},
	url = {<Go to ISI>://000075202300022},
	author = {Bowser, M. T. and Kranack, A. R. and Chen, D. D. Y.}
}
@article {4205,
	title = {Higher order equilibria and their effect on analyte migration behavior in capillary electrophoresis},
	journal = {Analytical Chemistry},
	volume = {70},
	number = {15},
	year = {1998},
	note = {ISI Document Delivery No.: 107VQTimes Cited: 38Cited Reference Count: 31},
	month = {Aug},
	pages = {3261-3270},
	type = {Article},
	abstract = {This paper presents a quantitative investigation into the effect of analyte-additive interactions on analyte migration behavior in capillary electrophoresis (CE) when both 1:1 and 1:2 stoichiometries are present. Equations based on the individual capacity factors for each interaction are derived to account for the effect of both first- and second-order equilibria. The analyte migration behavior is described using these equations with a full account of how the microscopic equilibrium constants and microscopic mobilities are combined to give the macroscopic values. The binding isotherms of interactions with both 1:1 and 1:2 stoichiometries are compared with those of a 1:1 stoichiometry. 4,4{\textquoteright}-Biphenol and 4-phenylphenol were chosen as analytes that undergo complexation with one and two hydroxypropyl-beta-cyclodextrin (HP-beta-CD) molecules; phenol was used as an analyte that interacts with only one HP-beta-CD molecule. The process of calculating higher order equilibrium constants and complex mobilities from the binding isotherms is demonstrated. The effects of experimental conditions, such as the additive concentration range and the number of data points, on the error in the calculated constants and the ability of the equations to accurately describe the experimental data are discussed. A comparison of the linear transformations of the binding isotherm with respect to their ability to detect higher order equilibria is made, and the advantage of using the capacity factor in CE is illustrated.},
	keywords = {AFFINITY, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, METAL-IONS, SELECTIVITY, SELECTORS, THEORETICAL ASPECTS, TIOCONAZOLE ENANTIOMERS, ZONE ELECTROPHORESIS},
	isbn = {0003-2700},
	url = {<Go to ISI>://000075232000034},
	author = {Bowser, M. T. and Chen, D. D. Y.}
}
@article {4209,
	title = {Properties of multivariate binding isotherms in capillary electrophoresis},
	journal = {Analytical Chemistry},
	volume = {70},
	number = {6},
	year = {1998},
	note = {ISI Document Delivery No.: ZC318Times Cited: 16Cited Reference Count: 30},
	month = {Mar},
	pages = {1076-1084},
	type = {Article},
	abstract = {When more than one complexation additive is used in capillary electrophoresis (CE), the migration behavior of an analyte can be described using contour plots and profile plots of the multivariate binding isotherms, At a certain concentration of one additive, the net electrophoretic mobility of the analyte is not affected by the concentration of the second additive, even though the second additive does alter the mobility of the analyte when used alone. The concentration of the first additive, in this situation, is defined as the dengsu concentration (dengsu means "same speed" in Chinese), The presence of a dengsu concentration for one additive is a strong indication that the second additive interacts with the analyte in a 1:1 (analyte-additive) stoichiometry, The binding isotherms in a profile plot can be used to unambiguously determine the binding stoichiometry of the analytes, as well as to determine the effect of interactions between the additives. The apparent complex mobilities obtained from the profile plots can also be used to determine whether there are interactions between the additives or whether the analyte can bind both additives at the same time.},
	keywords = {AFFINITY, BETA-CYCLODEXTRIN, CHIRAL SEPARATION, POLYETHERS, RESOLUTION, SELECTIVITY, THEORETICAL ASPECTS, TIOCONAZOLE ENANTIOMERS},
	isbn = {0003-2700},
	url = {<Go to ISI>://000072565200004},
	author = {Bowser, M. T. and Kranack, A. R. and Chen, D. D. Y.}
}
@article {3911,
	title = {Prediction of the migration behavior of analytes in capillary electrophoresis based on three fundamental parameters},
	journal = {Journal of Chromatography A},
	volume = {781},
	number = {1-2},
	year = {1997},
	note = {ISI Document Delivery No.: YC198Times Cited: 11Cited Reference Count: 309th International Symposium on High Performance Capillary Electrophoresis and Related Microscale TechniquesJAN 26-30, 1997ORLANDO, FL},
	month = {Sep},
	pages = {23-34},
	type = {Proceedings Paper},
	abstract = {The prediction of analyte migration behavior in capillary electrophoresis (CE) is essential for rapid method development. The dynamic complexation model, based on 1:1 interactions, was used to accurately predict the apparent electrophoretic mobilities and the migration times of a group of deoxyribonucleotides (dNPs) at various concentrations of beta-cyclodextrin (beta-CD). The electrophoretic mobility of the analyte, the electrophoretic mobility of the analyte-additive complex and the equilibrium constant are the three fundamental parameters required to determine the mobility of an analyte. The apparent migration time of the analyte can be predicted once the electroosmotic mobility and relative viscosity of the solution are known. Optimum separation conditions can be determined based on these parameters. Excellent agreement between observed analyte migration behavior and predicted values was demonstrated, with relative errors being often less than 1\%. The theory was tested repeatedly under various conditions in order to assess its predictive capabilities and limitations. Analysis by molecular modelling, in conjunction with calculated electrophoretic parameters and equilibrium constants, provided deeper insight into the probable mechanisms of the separation process at the molecular level. (C) 1997 Elsevier Science B.V.},
	keywords = {AFFINITY, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, CONSTANTS, deoxyribonucleotides, ELECTROKINETIC CHROMATOGRAPHY, ENANTIOMERS, migration behaviour, migration time prediction, MODEL, OPTIMIZATION, SELECTORS, TIOCONAZOLE},
	isbn = {0021-9673},
	url = {<Go to ISI>://A1997YC19800005},
	author = {BritzMcKibbin, P. and Chen, D. D. Y.}
}
@article {4099,
	title = {Quantitative description of analyte migration behavior based on the dynamic complexation model in capillary electrophoresis},
	journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie},
	volume = {75},
	number = {5},
	year = {1997},
	note = {ISI Document Delivery No.: XF492Times Cited: 20Cited Reference Count: 27},
	month = {May},
	pages = {507-517},
	type = {Article},
	abstract = {A theory based on dynamic complexation is used to describe analyte migration behavior in capillary electrophoresis (CE). This theory is based on a one-phase system, instead of the commonly accepted two-phase system. The migration behavior of an analyte is described by three parameters (the electrophoretic mobility of the free analyte, the electrophoretic mobility of the analyte-additive complex, and the equilibrium constant (formation constant) that determines the fractions of the free analyte and the complex at a certain additive concentration). Varying the additive concentration shifts the equilibrium and changes the viscosity of the background electrolyte. Viscosity correction is crucial in interpreting the observed migration behavior of analytes. While electroosmotic flow in a capillary often varies from one capillary to another, the viscosity of a buffer is characteristic of the buffer composition and is constant for each buffer. The electrophoretic mobility of a certain species and the equilibrium constant are intrinsic properties and are less sensitive to changes in the environment. Understanding these relationships is indispensable in CE method development and method validation. A universal resolution equation is proposed, with a separation factor that has taken both the electrophoretic mobilities and equilibria into consideration. This resolution equation gives clear guidance for the optimization of CE separations. A group of nucleosides and their phosphates are used as analytes, and P-cyclodextrin is used as the additive in the model system studied in this paper. Both the observed analyte migration behavior and the resolution of analytes agree well with this theory.},
	keywords = {ACIDS, BETA-CYCLODEXTRIN, BINDING, capacity factor, CHIRAL SEPARATION, CORRECTION, dynamic complexation capillary electrophoresis, ELECTROKINETIC CHROMATOGRAPHY, mobility, nucleoside and, nucleotide separation, RESOLUTION, resolution equation, VISCOSITY},
	isbn = {0008-4042},
	url = {<Go to ISI>://A1997XF49200005},
	author = {Peng, X. J. and Bebault, G. M. and Sacks, S. L. and Chen, D. D. Y.}
}
@article {3909,
	title = {Quantitative description of migration behavior of porphyrins based on the dynamic complexation model in a nonaqueous capillary electrophoresis system},
	journal = {Electrophoresis},
	volume = {18},
	number = {1},
	year = {1997},
	note = {ISI Document Delivery No.: WH231Times Cited: 47Cited Reference Count: 48},
	month = {Jan},
	pages = {82-91},
	type = {Article},
	abstract = {The effect of an additive (Brij 35) on the mobilities of a group of porphyrin acids is quantitatively characterized based on a 1:I dynamic complexation model. Varying additive concentration shifts the equilibrium and changes the viscosity of the background electrolyte. The equilibrium constant, the electrophoretic mobility of the free analyte, and the electrophoretic mobility of the complex are identified as the parameters necessary to describe the analytes{\textquoteright} migration behavior. Several statistical methods for obtaining these parameters are discussed. The equilibrium constants and complex mobilities are calculated using three different linear regression methods. The weighted y-recip-rocal method was preferred because it gives smaller error, and the data points are evenly distributed along the concentration axis. These values are confirmed using a nonlinear regression to ensure that the proper weighting was used in the linear regression plots. The parameters are then used to predict the apparent mobilities of the analytes over the entire additive concentration range, allowing the optimum separation conditions to be identified. For disclike molecules, such as porphyrins, the mobility is determined by the orientation of the molecule in an electric field, in addition to their size and charge. The strength of binding between the porphyrins and Brij 35 depends on the number of binding sites and the solvation shell.},
	keywords = {additives, AFFINITY, ANIONS, BETA-CYCLODEXTRIN, BINDING, CHIRAL SEPARATION, DYNAMIC COMPLEXATION, ENANTIOMERS, nonaqueous capillary electrophoresis, PARAMETERS, PORPHYRIN, SELECTIVITY, SELECTORS, separation theory, TIOCONAZOLE, ZONE ELECTROPHORESIS},
	isbn = {0173-0835},
	url = {<Go to ISI>://A1997WH23100016},
	author = {Bowser, M. T. and Sternberg, E. D. and Chen, D. D. Y.}
}
