George Horvai - Profile on Academia.edu (original) (raw)
Papers by George Horvai
Physical Chemistry Chemical Physics, 2008
Molecular level structure of the liquid/liquid interface. Molecular dynamics simulation and ITIM ... more Molecular level structure of the liquid/liquid interface. Molecular dynamics simulation and ITIM analysis of the water-CCl 4 system
Journal of The Serbian Chemical Society, 2011
Journal of Molecular Liquids, Dec 1, 2012
Molecular dynamics simulation of the liquid-vapour interface of SPC/E water have been performed o... more Molecular dynamics simulation of the liquid-vapour interface of SPC/E water have been performed on the canonical (N,V,T) ensemble in twelve temperatures ranging from 300 to 500 K using systems of two different sizes in order to locate the percolation threshold of the lateral hydrogen bonding network of surface waters. This infinite network, present at ambient conditions, is found to break up at about 450 K, i.e., 200 K below the critical temperature of the model, and hence the breakup of this two dimensional hydrogen bonding network at the liquid surface well precedes that of the three dimensional hydrogen bonding network in the bulk phase. We found that surface percolation can be described as a random bond percolation, i.e., all water molecules can form up to 3 lateral hydrogen bonds with their neighbours in the surface layer, and the formation or breaking of any of these possible hydrogen bonds is independent of that of all the other ones.
Computer simulation and ITIM analysis of the surface of water–methanol mixtures containing traces of water
Journal of Molecular Liquids, Apr 1, 2010
Molecular dynamics computer simulation of the surface of watermethanol mixtures containing only ... more Molecular dynamics computer simulation of the surface of watermethanol mixtures containing only traces (ie, 3%, 5% and 10%) of water are performed on the canonical (N,V,T) ensemble at 298 K. The properties of the surface are analyzed in terms of the novel ITIM method. ...
Mikrochimica Acta, 1988
Band broadening in a large volume wall-jet cell electrochemical detector for liquid chromatograph... more Band broadening in a large volume wall-jet cell electrochemical detector for liquid chromatography has been studied. Two regimes of stable operation were found which correlated well with the formation of smooth flow patterns. Smooth flow is also found to be important for avoiding erroneous results caused by backmixing.
Analytical Sciences/Supplements Proceedings of IUPAC International Congress on Analytical Sciences 2001 (ICAS 2001), 2002
Different approaches are used for the modeling of the liquid/liquid interface and the adsorption ... more Different approaches are used for the modeling of the liquid/liquid interface and the adsorption of SCN-anions: (A) the self-consistent mean field approach, (B) Metropolis Monte Carlo and (C) Molecular Dynamics Simulation. The general picture of the interface agrees quite well with the three methods. Methods B and C provide in principle a more accurate picture of details and of adsorption but they are still not practical to compare a large number of systems of dilute electrolytes which the SCF method can easily do.
Journal of Chemical Information and Computer Sciences, Aug 8, 2000
It deals with revisiting these topics. The results have shown that the database has substantially... more It deals with revisiting these topics. The results have shown that the database has substantially improved its coverage by editorial reorganizations in 1994. The only open problem which has been revealed is a somewhat excessive emphasis given to the coverage of the journals on the lower tail of the journal distribution. The suggestion is made to reduce this emphasis in favor of an even more complete coverage of some "titled" analytical journals.
Talanta, 2017
A simple and efficient method is presented for assessing molecularly imprinted polymers (MIP) and... more A simple and efficient method is presented for assessing molecularly imprinted polymers (MIP) and other sorbents from the point of view of practical applications. The adsorption isotherms of the compounds, which need to be separated or detected in an application, are constructed from a small number of measured points on a log-log chart and then are compared graphically. Despite its simplicity and robustness this method reveals the information needed for optimal selection between MIPs and alternative sorbents. The design of separation or detection methods with MIPs is also supported by the proposed graphical isotherm comparison. Many experimental isotherms are presented supporting the proposed method.
Journal of Chromatography A, Dec 1, 2005
Molecularly imprinted polymers (MIP) have recently been prepared inside the pores of silica based... more Molecularly imprinted polymers (MIP) have recently been prepared inside the pores of silica based HPLC packing materials. Detailed physical and chromatographic characterization of such a silica-MIP composite material is presented. The chromatographic peak shape obtained with the uniformly sized spherical silica-MIP composite is mainly determined by the nonlinear adsorption isotherm. Comparison of the composite with the conventional sieved and grinded bulk MIP is therefore based on the nonlinear isotherm and not on retention factors and plate numbers.
Molecularly imprinted polymers for analytical chemistry
Chemia Analityczna, 2005
A critical assessment of the suitability ofmolecularly imprinted polymers (MIP) for HPLC and bind... more A critical assessment of the suitability ofmolecularly imprinted polymers (MIP) for HPLC and binding assays is presented. The goal of this paper is to draw attention to a few simple facts about MIPs which are relevant foran analytical chemist but which have apparently not yet been collected in such concise form.
Inorganic Salts Trapped in Neutral Carrier Ion-Selective Electrode Membranes form Ion-Exchange Sites
Journal Of Macromolecular Science, Part A, Apr 1, 1972
Analytica Chimica Acta, Aug 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Chromatography A, Jun 1, 2006
Molecularly imprinted polymers (MIPs) have frequently been characterized by quantities which are ... more Molecularly imprinted polymers (MIPs) have frequently been characterized by quantities which are easily determined from experiments but have no theoretical foundation. This makes it difficult to compare different MIP preparations or to transfer MIP based methods to different experimental conditions. Since the adsorption isotherms of MIPs are markedly nonlinear, one can build a better characterization strategy on isotherms as shown by examples in this paper.
Analytica Chimica Acta, Dec 1, 1976
Two types of commercial lead(II)-selective electrode, the Orion 94-82 and the R%iSka lead Selectr... more Two types of commercial lead(II)-selective electrode, the Orion 94-82 and the R%iSka lead Selectrode, are compared. Calibration curves were determined in both buffered and unbuffered lead-ion solutions repeatedly for several weeks. Selectivities with respect to copper(silver(I), mercury(II), lron(III), zinc and cadmium were examined as well as the pH response by the mixed solution method. The response times of the electrodes were also studied.
Application of Ion-Selective Electrodes in Flowing Systems; Problems Related to the Measurements in Low Concentration Ranges
Elsevier eBooks, 1980
Analytical followup of the gamma initiated synthesis of a molecularly imprinted polymer
Analytica Chimica Acta, Feb 1, 2008
A molecularly imprinted polymer (MIP) for the template phenytoin has been prepared by gamma initi... more A molecularly imprinted polymer (MIP) for the template phenytoin has been prepared by gamma initiated copolymerization of methacrylamide and ethylene glycol dimethacrylate. The progress of polymerization was studied by measuring the monomer conversions and the template binding properties of the resulting polymers, respectively. The consumption rate of the two monomers showed different course. There was no difference observed in the polymerization rates of the MIP and the control polymer (NIP). The template binding properties of the MIP and the NIP changed considerably with the progress of the polymerization process and became similar to those of the thermally initiated polymers after full conversion.
Journal of Physical Chemistry C, Jun 19, 2019
Amphiphilic surfactants are changing the surface tension of solutions by adsorbing at its surface... more Amphiphilic surfactants are changing the surface tension of solutions by adsorbing at its surface. In general, however, little is known about the actual distribution of the surface tension across the interface, as well as about the extent of the contribution of different moieties to the surface tension. Here, we consider the liquid-vapor interface of the solutions of five different amphiphilic molecules, representative of anionic, cationic and non-ionic (alcoholic) surfactants. We investigate, by means of molecular dynamics simulation, the contribution of various chemical species and moieties to the surface tension distribution in these aqueous solutions at various surface coverages. We find that the headgroups of alcoholic surfactants give a negligible contribution to the surface tension. The opposite is true for ionic surfactants, whose effect depends on their 'hardness' within the Hofmeister series, even though there is a large compensation between ions and counterions. In addition, we find that water molecules contribute negatively to the surface tension when they are hydrating the ionic headgroups and counterions, instead of being exposed to the vapor phase.
Structure of the Acetone Liquid−Vapor Interface as Seen from Monte Carlo Simulations
Journal of Physical Chemistry B, Jun 1, 2005
The orientational order of the molecules at the liquid-vapor interface of acetone has been invest... more The orientational order of the molecules at the liquid-vapor interface of acetone has been investigated by computer simulation. To fully describe the orientational preferences of the acetone molecules, the bivariate joint distribution of two independent orientational parameters has been determined at different layers of the interface. The strength of the orientational ordering of the interfacial molecules has been found to be liquid-like rather than crystal-like. The obtained results have revealed that the interfacial acetone molecules have dual orientational preferences. The main symmetry axis of the molecules declines by about 50-70 degrees from the interface normal axis, pointing toward the liquid phase in both of the preferred orientations. However, the plane of the molecules in the orientation preferred on the liquid side of the interface is perpendicular to the interfacial plane, whereas the other preferred orientation, which is present on the vapor side of the interface, corresponds to the alignment obtained from this orientation by an almost 90 degrees rotation around the main symmetry axis. Because the population of the liquid side is higher than that of the vapor side of the interface, the first of the two preferred orientations is the dominant alignment over the entire interface, in good agreement with recent experimental findings (Chen, H.; Gan, W.; Wu, B. H.; Wu, D.; Zhang, Z.; Wang, H. F. Chem. Phys. Lett. 2005, 408, 284).
Temperature and Pressure Dependence of the Properties of the Liquid−Liquid Interface. A Computer Simulation and Identification of the Truly Interfacial Molecules Investigation of the Water−Benzene System
Journal of Physical Chemistry C, Nov 17, 2010
ABSTRACT
Physical Chemistry Chemical Physics, 2008
Molecular level structure of the liquid/liquid interface. Molecular dynamics simulation and ITIM ... more Molecular level structure of the liquid/liquid interface. Molecular dynamics simulation and ITIM analysis of the water-CCl 4 system
Journal of The Serbian Chemical Society, 2011
Journal of Molecular Liquids, Dec 1, 2012
Molecular dynamics simulation of the liquid-vapour interface of SPC/E water have been performed o... more Molecular dynamics simulation of the liquid-vapour interface of SPC/E water have been performed on the canonical (N,V,T) ensemble in twelve temperatures ranging from 300 to 500 K using systems of two different sizes in order to locate the percolation threshold of the lateral hydrogen bonding network of surface waters. This infinite network, present at ambient conditions, is found to break up at about 450 K, i.e., 200 K below the critical temperature of the model, and hence the breakup of this two dimensional hydrogen bonding network at the liquid surface well precedes that of the three dimensional hydrogen bonding network in the bulk phase. We found that surface percolation can be described as a random bond percolation, i.e., all water molecules can form up to 3 lateral hydrogen bonds with their neighbours in the surface layer, and the formation or breaking of any of these possible hydrogen bonds is independent of that of all the other ones.
Computer simulation and ITIM analysis of the surface of water–methanol mixtures containing traces of water
Journal of Molecular Liquids, Apr 1, 2010
Molecular dynamics computer simulation of the surface of watermethanol mixtures containing only ... more Molecular dynamics computer simulation of the surface of watermethanol mixtures containing only traces (ie, 3%, 5% and 10%) of water are performed on the canonical (N,V,T) ensemble at 298 K. The properties of the surface are analyzed in terms of the novel ITIM method. ...
Mikrochimica Acta, 1988
Band broadening in a large volume wall-jet cell electrochemical detector for liquid chromatograph... more Band broadening in a large volume wall-jet cell electrochemical detector for liquid chromatography has been studied. Two regimes of stable operation were found which correlated well with the formation of smooth flow patterns. Smooth flow is also found to be important for avoiding erroneous results caused by backmixing.
Analytical Sciences/Supplements Proceedings of IUPAC International Congress on Analytical Sciences 2001 (ICAS 2001), 2002
Different approaches are used for the modeling of the liquid/liquid interface and the adsorption ... more Different approaches are used for the modeling of the liquid/liquid interface and the adsorption of SCN-anions: (A) the self-consistent mean field approach, (B) Metropolis Monte Carlo and (C) Molecular Dynamics Simulation. The general picture of the interface agrees quite well with the three methods. Methods B and C provide in principle a more accurate picture of details and of adsorption but they are still not practical to compare a large number of systems of dilute electrolytes which the SCF method can easily do.
Journal of Chemical Information and Computer Sciences, Aug 8, 2000
It deals with revisiting these topics. The results have shown that the database has substantially... more It deals with revisiting these topics. The results have shown that the database has substantially improved its coverage by editorial reorganizations in 1994. The only open problem which has been revealed is a somewhat excessive emphasis given to the coverage of the journals on the lower tail of the journal distribution. The suggestion is made to reduce this emphasis in favor of an even more complete coverage of some "titled" analytical journals.
Talanta, 2017
A simple and efficient method is presented for assessing molecularly imprinted polymers (MIP) and... more A simple and efficient method is presented for assessing molecularly imprinted polymers (MIP) and other sorbents from the point of view of practical applications. The adsorption isotherms of the compounds, which need to be separated or detected in an application, are constructed from a small number of measured points on a log-log chart and then are compared graphically. Despite its simplicity and robustness this method reveals the information needed for optimal selection between MIPs and alternative sorbents. The design of separation or detection methods with MIPs is also supported by the proposed graphical isotherm comparison. Many experimental isotherms are presented supporting the proposed method.
Journal of Chromatography A, Dec 1, 2005
Molecularly imprinted polymers (MIP) have recently been prepared inside the pores of silica based... more Molecularly imprinted polymers (MIP) have recently been prepared inside the pores of silica based HPLC packing materials. Detailed physical and chromatographic characterization of such a silica-MIP composite material is presented. The chromatographic peak shape obtained with the uniformly sized spherical silica-MIP composite is mainly determined by the nonlinear adsorption isotherm. Comparison of the composite with the conventional sieved and grinded bulk MIP is therefore based on the nonlinear isotherm and not on retention factors and plate numbers.
Molecularly imprinted polymers for analytical chemistry
Chemia Analityczna, 2005
A critical assessment of the suitability ofmolecularly imprinted polymers (MIP) for HPLC and bind... more A critical assessment of the suitability ofmolecularly imprinted polymers (MIP) for HPLC and binding assays is presented. The goal of this paper is to draw attention to a few simple facts about MIPs which are relevant foran analytical chemist but which have apparently not yet been collected in such concise form.
Inorganic Salts Trapped in Neutral Carrier Ion-Selective Electrode Membranes form Ion-Exchange Sites
Journal Of Macromolecular Science, Part A, Apr 1, 1972
Analytica Chimica Acta, Aug 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Chromatography A, Jun 1, 2006
Molecularly imprinted polymers (MIPs) have frequently been characterized by quantities which are ... more Molecularly imprinted polymers (MIPs) have frequently been characterized by quantities which are easily determined from experiments but have no theoretical foundation. This makes it difficult to compare different MIP preparations or to transfer MIP based methods to different experimental conditions. Since the adsorption isotherms of MIPs are markedly nonlinear, one can build a better characterization strategy on isotherms as shown by examples in this paper.
Analytica Chimica Acta, Dec 1, 1976
Two types of commercial lead(II)-selective electrode, the Orion 94-82 and the R%iSka lead Selectr... more Two types of commercial lead(II)-selective electrode, the Orion 94-82 and the R%iSka lead Selectrode, are compared. Calibration curves were determined in both buffered and unbuffered lead-ion solutions repeatedly for several weeks. Selectivities with respect to copper(silver(I), mercury(II), lron(III), zinc and cadmium were examined as well as the pH response by the mixed solution method. The response times of the electrodes were also studied.
Application of Ion-Selective Electrodes in Flowing Systems; Problems Related to the Measurements in Low Concentration Ranges
Elsevier eBooks, 1980
Analytical followup of the gamma initiated synthesis of a molecularly imprinted polymer
Analytica Chimica Acta, Feb 1, 2008
A molecularly imprinted polymer (MIP) for the template phenytoin has been prepared by gamma initi... more A molecularly imprinted polymer (MIP) for the template phenytoin has been prepared by gamma initiated copolymerization of methacrylamide and ethylene glycol dimethacrylate. The progress of polymerization was studied by measuring the monomer conversions and the template binding properties of the resulting polymers, respectively. The consumption rate of the two monomers showed different course. There was no difference observed in the polymerization rates of the MIP and the control polymer (NIP). The template binding properties of the MIP and the NIP changed considerably with the progress of the polymerization process and became similar to those of the thermally initiated polymers after full conversion.
Journal of Physical Chemistry C, Jun 19, 2019
Amphiphilic surfactants are changing the surface tension of solutions by adsorbing at its surface... more Amphiphilic surfactants are changing the surface tension of solutions by adsorbing at its surface. In general, however, little is known about the actual distribution of the surface tension across the interface, as well as about the extent of the contribution of different moieties to the surface tension. Here, we consider the liquid-vapor interface of the solutions of five different amphiphilic molecules, representative of anionic, cationic and non-ionic (alcoholic) surfactants. We investigate, by means of molecular dynamics simulation, the contribution of various chemical species and moieties to the surface tension distribution in these aqueous solutions at various surface coverages. We find that the headgroups of alcoholic surfactants give a negligible contribution to the surface tension. The opposite is true for ionic surfactants, whose effect depends on their 'hardness' within the Hofmeister series, even though there is a large compensation between ions and counterions. In addition, we find that water molecules contribute negatively to the surface tension when they are hydrating the ionic headgroups and counterions, instead of being exposed to the vapor phase.
Structure of the Acetone Liquid−Vapor Interface as Seen from Monte Carlo Simulations
Journal of Physical Chemistry B, Jun 1, 2005
The orientational order of the molecules at the liquid-vapor interface of acetone has been invest... more The orientational order of the molecules at the liquid-vapor interface of acetone has been investigated by computer simulation. To fully describe the orientational preferences of the acetone molecules, the bivariate joint distribution of two independent orientational parameters has been determined at different layers of the interface. The strength of the orientational ordering of the interfacial molecules has been found to be liquid-like rather than crystal-like. The obtained results have revealed that the interfacial acetone molecules have dual orientational preferences. The main symmetry axis of the molecules declines by about 50-70 degrees from the interface normal axis, pointing toward the liquid phase in both of the preferred orientations. However, the plane of the molecules in the orientation preferred on the liquid side of the interface is perpendicular to the interfacial plane, whereas the other preferred orientation, which is present on the vapor side of the interface, corresponds to the alignment obtained from this orientation by an almost 90 degrees rotation around the main symmetry axis. Because the population of the liquid side is higher than that of the vapor side of the interface, the first of the two preferred orientations is the dominant alignment over the entire interface, in good agreement with recent experimental findings (Chen, H.; Gan, W.; Wu, B. H.; Wu, D.; Zhang, Z.; Wang, H. F. Chem. Phys. Lett. 2005, 408, 284).
Temperature and Pressure Dependence of the Properties of the Liquid−Liquid Interface. A Computer Simulation and Identification of the Truly Interfacial Molecules Investigation of the Water−Benzene System
Journal of Physical Chemistry C, Nov 17, 2010
ABSTRACT