@article {1107,
title = {Enumeration algorithm for determination of binding constants in capillary electrophoresis},
journal = {Analytical Chemistry},
volume = {77},
number = {8},
year = {2005},
note = {ISI Document Delivery No.: 919FZTimes Cited: 11Cited Reference Count: 16},
month = {Apr},
pages = {2415-2420},
type = {Article},
abstract = {With more accurate simulation models and more efficient algorithms becoming available, the binding constants of an affinity interaction can be obtained from much simpler experiments using capillary electrophoresis. With the enumeration algorithm, all possible combinations of the binding constant and the complex mobility in certain ranges that could result in the experimental migration time of an injected analyte are extracted from a 3-D surface, which depicts the migration times resulting from different values of the binding constant and the mobility of the complex formed between the interacting pair, to form a 2-D curve. When the experimental conditions are changed, the analyte migration time will also change. A new 2-D curve can be constructed from another 3-D surface on the basis of the pairs of binding constants and complex mobility values that could result in the new migration time. Because the true binding constant and complex mobility values have to be the same for both experimental conditions under the same temperature, there has to be a point where both 2-D curves will converge. The coordinates of the converging point give the values for a binding constant and a complex mobility that will fit all 2-D curves generated under certain experimental conditions. p-Nitrophenol is used as the analyte, beta-cyclodextrin is used as the additive, and a one-cell model is used to simulate affinity CE. The experimental conditions that can improve the accuracy of the binding constants are discussed.},
keywords = {DYNAMIC COMPLEXATION, ERROR PROPAGATION, MIGRATION BEHAVIOR, MONTE-CARLO-SIMULATION, NUMERICAL-SIMULATION, QUANTITATIVE DESCRIPTION, RANGE, RECTANGULAR HYPERBOLAE, SEPARATION, ZONE-ELECTROPHORESIS},
isbn = {0003-2700},
url = {://000228605100018},
author = {Fang, N. and Chen, D. D. Y.}
}
@article {849,
title = {Determination of shapes and maximums of analyte peaks based on solute mobilitiess in capillary electrophoresis},
journal = {Analytical Chemistry},
volume = {76},
number = {6},
year = {2004},
note = {ISI Document Delivery No.: 803IQTimes Cited: 11Cited Reference Count: 28},
month = {Mar},
pages = {1708-1714},
type = {Article},
abstract = {In capillary electrophoresis, the relative orders of mobilities of analyte, additive, and the complex formed determine the analyte peak shape in a way similar to the way the binding isotherms determine the peak shapes in chromatography. The three mobilities allow six possible orders; each produces a characteristic peak shape in CE. Equations describing the analyte migration in a CE system with the presence of mobility-changing additives can be implemented into computer programs to predict the migration times of the analyte peak maximums, and the predicted migration times agree well with the experimental results.},
keywords = {DISPERSION, DYNAMIC COMPLEXATION, FLOW, MIGRATION BEHAVIOR, NUMERICAL-SIMULATION, pressure, QUANTITATIVE DESCRIPTION, SEPARATIONS, ZONE-ELECTROPHORESIS},
isbn = {0003-2700},
url = {://000220225200023},
author = {Fang, N. and Ting, E. and Chen, D. D. Y.}
}
@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 = {://000174699400008},
author = {Britz-McKibbin, P. and Chen, D. D. Y.}
}
@article {477,
title = {Chiral separation of benzoporphyrin derivative mono- and diacids by laser induced fluorescence-capillary electrophoresis},
journal = {Electrophoresis},
volume = {23},
number = {1},
year = {2002},
note = {ISI Document Delivery No.: 513ZATimes Cited: 9Cited Reference Count: 42},
month = {Jan},
pages = {93-101},
type = {Article},
abstract = {A method for the separation of benzoporphyrin derivative mono- and diacid (BPDMA, BPDDA) enantiomers; by laser induced fluorescence-capillary electrophoresis (LIF-CE) has been developed. By using 300 mm borate buffer, pH 9.2, 25 mm sodium cholate and 10\% acetronitrile as electrolyte, +10 kV electrokinetic sampling injection of 2 s and an applied +20 kV voltage across the ends of a 37 cm capillary (30 cm to the detector, 50 mum ID), all six BPD stereoisomers; were baseline-separated within 20 min. Formation constants, free electrophoretic and complexation mobilities with borate and cholate were determined based on dynamic complexation capillary electrophoresis theory. The BPD enantiomers can be quantitatively determined in the range of 10(-2)-10(-5) mg mL(-1). The correlation coefficients (r(2)) of the least-squares linear regression analysis of the BPD enantiomers are in the range of 0.9914-0.9997. Their limits of detection are 2.18-3.5 x 10(-3) mg mL(-1). The relative standard deviations for the separation were 2.90-4.64\% (n = 10). In comparison with high-performance liquid chromatography (HPLC), CE has better resolution and efficiency. This separation method was successfully applied to the BPD enantiomers obtained from a matrix of bovine serum and from liposomally formulated material as well as from studies with rat, dog and human microsomes.},
keywords = {benzoporphyrin derivative mono- and diacids, BORATE COMPLEXATION, capillary electrophoresis, DYNAMIC COMPLEXATION MODEL, MIGRATION BEHAVIOR, PERFORMANCE LIQUID-CHROMATOGRAPHY, PHOTODYNAMIC THERAPY, PHOTOSENSITIZER, porphyrins, QUANTITATIVE DESCRIPTION, SYSTEM, TUMOR, ZONE ELECTROPHORESIS},
isbn = {0173-0835},
url = {://000173410100014},
author = {Peng, X. J. and Sternberg, E. and Dolphin, D.}
}
@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 {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.}
}