@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 = {://000079042200026},
author = {Bowser, M. T. and Chen, D. D. Y.}
}
@article {4317,
title = {The effects of a mixture of charged and neutral additives on analyte migration behavior in capillary electrophoresis},
journal = {Electrophoresis},
volume = {19},
number = {3},
year = {1998},
note = {ISI Document Delivery No.: ZD713Times Cited: 14Cited Reference Count: 45},
month = {Mar},
pages = {388-396},
type = {Article},
abstract = {Multicomponent additives, such as derivatized cyclodextrins with various degrees of substitution, can be considered single-component additives as long as the fraction of each component remains constant. In this paper, equations are derived describing the effect of such additives on the migration behavior of analytes. These equations are used in the study of capillary electrophoresis (CE) systems with differentially charged cyclodextrins as additives. For weakly acidic analytes, the binding with highly negatively charged sulfobutyl ether beta-cyclodextrin (SBE-beta-CD) increases their negative electrophoretic mobility, while the binding with neutral hydroxypropyl-beta-cyclodextrin (HP-beta-CD) decreases their negative mobility. By obtaining the equilibrium constants and mobilities for each additive with each analyte (in this case, phenol, 2-naphthol and 1-naphthol), the migration behavior of these analytes in CE systems is quantitatively predicted at various concentrations of mixtures of the two additives. The properties of the contour lines in the binding isotherm surfaces of such CE systems are discussed.},
keywords = {ANALYTE, ASPECTS, BETA-CYCLODEXTRIN, CHIRAL, ELECTROPHORESIS, MICELLAR ELECTROKINETIC CHROMATOGRAPHY, MIGRATION BEHAVIOR, MOBILE PHASES, multicomponent additives, RESOLUTION, SELECTIVITY, SEPARATION, separation theory, STATIONARY PHASE, THEORETICAL, TIOCONAZOLE ENANTIOMERS, two-additive capillary, ZONE ELECTROPHORESIS},
isbn = {0173-0835},
url = {://000072716000004},
author = {Kranack, A. R. and Bowser, M. T. and Britz-McKibbin, P. 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 = {://000075232000034},
author = {Bowser, M. T. and Chen, D. D. Y.}
}
@article {4203,
title = {Monte Carlo simulation of error propagation in the determination of binding constants from rectangular hyperbolae. 1. Ligand concentration range and binding constant},
journal = {Journal of Physical Chemistry A},
volume = {102},
number = {41},
year = {1998},
note = {ISI Document Delivery No.: 132EFTimes Cited: 36Cited Reference Count: 50},
month = {Oct},
pages = {8063-8071},
type = {Article},
abstract = {Rectangular hyperbolae have been used both to estimate equilibrium constants and to describe chemical processes dictated by equilibria. The propagation of error from the experimental measurements to the estimated constants, however, has not been well understood. In this paper, simulated experiments are used in a Monte Carlo analysis to compare the distributions of binding constants estimated by various calculation methods under different experimental conditions. The necessity of matching the range of additive (ligand) concentrations to the binding constant of the chemical interaction is demonstrated. It is shown that the relative error in the binding constant estimate is lower when the additive concentrations cover the central to upper portion of the binding isotherm (i.e., where the fraction of analyte complexed is above 0.5). The difference in the slope of the binding isotherm at the lowest and highest additive concentration used for the measurements is a good indicator of the reliability of the binding constant estimated under a specific set of conditions.},
keywords = {1-1 MOLECULAR-COMPLEXES, ASSOCIATION CONSTANTS, capillary electrophoresis, COMPLEXATION MODEL, CONCENTRATION-DEPENDENT TRANSPORT, dynamic, MICHAELIS-MENTEN PARAMETERS, MIGRATION BEHAVIOR, QUANTITATIVE DESCRIPTION, SPECTROPHOTOMETRIC DATA, TIOCONAZOLE ENANTIOMERS},
isbn = {1089-5639},
url = {://000076616800026},
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 = {://000072565200004},
author = {Bowser, M. T. and Kranack, A. R. and Chen, D. D. Y.}
}