The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform
Laurence Nicod - One of the best experts on this subject based on the ideXlab platform.
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Supercoiled circular DNA and protein retention in non-equilibrium chromatography temperature and velocity dependence: testimony of a transition.
Journal of Chromatography A, 2002Co-Authors: François Xavier Perrin, Mireille Thomassin, Christiane Guinchard, Carol Courderot Masuyer, Tong-thanh Truong, Joëlle Millet, Jean Pierre Chaumont, Yves Claude Guillaum, Laurence NicodAbstract:Non-equilibrium chromatography (NEC) is a chromatographic mode for the rapid separation of polymers. The retention behavior of various proteins (human, chicken, bovine serum albumin) and supercoiled circular double-stranded DNA (plasmids) was investigated using a phosphate buffer as a mobile phase at different velocities and column temperatures with a C1 column with very low-Packing Particle diameter as a stationary phase. It was shown that the two factors (temperature and velocity) constituted important parameters in the retention mechanism of plasmids and proteins in NEC. The protein was retained more than the plasmid. At all the temperatures (5, 10, 15, 20, 25 degrees C) the plasmid retention increased over the entire flow-rate range (0.02-1.8 ml/min). For the protein, the retention curve presented a decrease in the relative retention time until a critical value of the mobile phase flow-rate, followed by an increase. The transition between the two well known NEC methods, slalom chromatography and hydrodynamic chromatography was clearly visualized for proteins at the lowest temperature, but did not appear for plasmids due to their strong compact structure.
Christiane Guinchard - One of the best experts on this subject based on the ideXlab platform.
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Supercoiled circular DNA and protein retention in non-equilibrium chromatography temperature and velocity dependence: testimony of a transition.
Journal of Chromatography A, 2002Co-Authors: François Xavier Perrin, Mireille Thomassin, Christiane Guinchard, Carol Courderot Masuyer, Tong-thanh Truong, Joëlle Millet, Jean Pierre Chaumont, Yves Claude Guillaum, Laurence NicodAbstract:Non-equilibrium chromatography (NEC) is a chromatographic mode for the rapid separation of polymers. The retention behavior of various proteins (human, chicken, bovine serum albumin) and supercoiled circular double-stranded DNA (plasmids) was investigated using a phosphate buffer as a mobile phase at different velocities and column temperatures with a C1 column with very low-Packing Particle diameter as a stationary phase. It was shown that the two factors (temperature and velocity) constituted important parameters in the retention mechanism of plasmids and proteins in NEC. The protein was retained more than the plasmid. At all the temperatures (5, 10, 15, 20, 25 degrees C) the plasmid retention increased over the entire flow-rate range (0.02-1.8 ml/min). For the protein, the retention curve presented a decrease in the relative retention time until a critical value of the mobile phase flow-rate, followed by an increase. The transition between the two well known NEC methods, slalom chromatography and hydrodynamic chromatography was clearly visualized for proteins at the lowest temperature, but did not appear for plasmids due to their strong compact structure.
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Mobile Phase Viscosity and Velocity Dependence on Protein Retention Using Nonequilibrium Chromatographic Techniques
Journal of Chromatographic Science, 2001Co-Authors: Yves Claude Guillaume, Mireille Thomassin, Christiane GuinchardAbstract:Nonequilibrium chromatography (NEC) is an alternative chromatographic procedure for the separation of macromolecules. The retardation of a protein series is studied using a phosphate buffer as a mobile phase with various concentrations of glycerol fraction (used as a viscosity modifier) at different mobile phase velocities and a C1 column with a very low Packing Particle diameter as a stationary phase. It is shown that the two factors (viscosity and velocity) of the mobile phase constituted important parameters in the retention mechanism of the proteins in NEC. The retardation velocity domain is divided into two regions. For low velocity regions, the protein retention decreased with a mobile phase velocity increase. This retention is enhanced above a critical value of the mobile phase velocity. The transition between the two well-known NEC methods, slalom chromatography and hydrodynamic chromatography, is clearly visualized for the first time for the protein retention of particular values of the mobile phase velocity.
Torgny Fornstedt - One of the best experts on this subject based on the ideXlab platform.
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Preparative Separation of Chiral Pharmaceutical Compounds - The Effects of Packing Particle Size, Pressure Limit and Column Geometry on Productivity and Solvent Consumption
2020Co-Authors: Martin Enmark, Jörgen Samuelsson, Torgny Fornstedt, Patrik ForssénAbstract:In this study, omeprazole was used as a model compound. Omeprazole and other related sulfoxidebenzimidazolesare used against gastric ulcersand have been extensively studied regarding chromatographic resolution techniques using several different chiral stationary phases.First, AstraZeneca launched Losec, a racemic mixture of RS-omeprazole. Facing loss of patent, the more potent S-enantiomer was developed and marketed as Nexium. Now the patent of Nexium is close expiration why methods for isolation of the pure S-enantiomer will be of importance for the generic pharmaceutical companies.The experimental model separation system represents a system with good selectivity and high solubility of the solute in the eluent. In this investigation the productivity optima for three different Particle sizes (5, 10 and 25 µm) at maximum system pressure ranging from 50 to 400 bars are studied. Two different optimizations cases were studied in depth. First,a process optimization with fixed column geometry is studied. The results clearly show that larger Packing materials have higher productivity at low pressure drops on the analytical size column.With increasing allowed pressure drops, over 200 bar, the smaller Packing materials have substantially higher productivity. The results also show that smaller Packing material will always have much lower solvent consumption compared to larger Particles.The second process optimization was performed with a fixed column volume, but the column geometry was variable. The results shows that the productivity obtained for the smaller Packing Particles materials was higher compared to the large for all allowed pressure drops. The productivity obtained for the small Particle compared to the large increased by 25-300 % while maintaining 50-300 % less solvent consumption for the purification of the first enantiomer.The addition of TEA seems to be unfavorable for all tested conditions.In conclusion, the optimization of the enantioseparation of omeprazole has been shown to be dependent on column Packing Particle size as well as column geometry. It has been demonstrated that all parameters need to be simultaneously optimized to reach a global productivity optima.
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Relative importance of column and adsorption parameters on the productivity in preparative liquid chromatography. I: investigation of a chiral separation system.
Journal of Chromatography A, 2013Co-Authors: Patrik Forssén, Jörgen Samuelsson, Torgny FornstedtAbstract:Starting out from an experimental chiral separation system we have used computer simulations for a systematic investigation on how the maximum productivity depends on changes in column length, Packing Particle size, column efficiency, back pressure, sample concentration/solubility, selectivity, retention factor of the first eluting component and monolayer saturation capacity. The study was performed by changing these parameters, one at a time, and then calculating the corresponding change in maximum productivity. The three most important parameters for maximum production rate was found to be (i) the selectivity (ii) the retention factor of the first eluting component and (iii) the column length. Surprisingly, the column efficiency and sample concentration/solubility were of minor importance. These findings can be used as rough guidelines for column selection, e.g. a low-efficiency column are more likely perform better, in terms of productivity, than a high-efficiency column that have higher retention factor for the first eluting component.
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enantioseparation of omeprazole effect of different Packing Particle size on productivity
Journal of Chromatography A, 2012Co-Authors: Martin Enmark, Jörgen Samuelsson, Patrik Forssén, Torgny FornstedtAbstract:Abstract Enantiomeric separation of omeprazole has been extensively studied regarding both product analysis and preparation using several different chiral stationary phases. In this study, the preparative chiral separation of omeprazole is optimized for productivity using three different columns packed with amylose tris (3,5-dimethyl phenyl carbamate) coated macroporous silica (5, 10 and 25 μm) with a maximum allowed pressure drop ranging from 50 to 400 bar. This pressure range both covers low pressure process systems (50–100 bar) and investigates the potential for allowing higher pressure limits in preparative applications in a future. The process optimization clearly show that the larger 25 μm Packing material show higher productivity at low pressure drops whereas with increasing pressure drops the smaller Packing materials have substantially higher productivity. Interestingly, at all pressure drops, the smaller Packing material result in lower solvent consumption (L solvent/kg product); the higher the accepted pressure drop, the larger the gain in reduced solvent consumption. The experimental adsorption isotherms were not identical for the different Packing material sizes; therefore all calculations were recalculated and reevaluated assuming identical adsorption isotherms (with the 10 μm isotherm as reference) which confirmed the trends regarding productivity and solvent consumption.
Mireille Thomassin - One of the best experts on this subject based on the ideXlab platform.
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Supercoiled circular DNA and protein retention in non-equilibrium chromatography temperature and velocity dependence: testimony of a transition.
Journal of Chromatography A, 2002Co-Authors: François Xavier Perrin, Mireille Thomassin, Christiane Guinchard, Carol Courderot Masuyer, Tong-thanh Truong, Joëlle Millet, Jean Pierre Chaumont, Yves Claude Guillaum, Laurence NicodAbstract:Non-equilibrium chromatography (NEC) is a chromatographic mode for the rapid separation of polymers. The retention behavior of various proteins (human, chicken, bovine serum albumin) and supercoiled circular double-stranded DNA (plasmids) was investigated using a phosphate buffer as a mobile phase at different velocities and column temperatures with a C1 column with very low-Packing Particle diameter as a stationary phase. It was shown that the two factors (temperature and velocity) constituted important parameters in the retention mechanism of plasmids and proteins in NEC. The protein was retained more than the plasmid. At all the temperatures (5, 10, 15, 20, 25 degrees C) the plasmid retention increased over the entire flow-rate range (0.02-1.8 ml/min). For the protein, the retention curve presented a decrease in the relative retention time until a critical value of the mobile phase flow-rate, followed by an increase. The transition between the two well known NEC methods, slalom chromatography and hydrodynamic chromatography was clearly visualized for proteins at the lowest temperature, but did not appear for plasmids due to their strong compact structure.
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Mobile Phase Viscosity and Velocity Dependence on Protein Retention Using Nonequilibrium Chromatographic Techniques
Journal of Chromatographic Science, 2001Co-Authors: Yves Claude Guillaume, Mireille Thomassin, Christiane GuinchardAbstract:Nonequilibrium chromatography (NEC) is an alternative chromatographic procedure for the separation of macromolecules. The retardation of a protein series is studied using a phosphate buffer as a mobile phase with various concentrations of glycerol fraction (used as a viscosity modifier) at different mobile phase velocities and a C1 column with a very low Packing Particle diameter as a stationary phase. It is shown that the two factors (viscosity and velocity) of the mobile phase constituted important parameters in the retention mechanism of the proteins in NEC. The retardation velocity domain is divided into two regions. For low velocity regions, the protein retention decreased with a mobile phase velocity increase. This retention is enhanced above a critical value of the mobile phase velocity. The transition between the two well-known NEC methods, slalom chromatography and hydrodynamic chromatography, is clearly visualized for the first time for the protein retention of particular values of the mobile phase velocity.
François Xavier Perrin - One of the best experts on this subject based on the ideXlab platform.
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Supercoiled circular DNA and protein retention in non-equilibrium chromatography temperature and velocity dependence: testimony of a transition.
Journal of Chromatography A, 2002Co-Authors: François Xavier Perrin, Mireille Thomassin, Christiane Guinchard, Carol Courderot Masuyer, Tong-thanh Truong, Joëlle Millet, Jean Pierre Chaumont, Yves Claude Guillaum, Laurence NicodAbstract:Non-equilibrium chromatography (NEC) is a chromatographic mode for the rapid separation of polymers. The retention behavior of various proteins (human, chicken, bovine serum albumin) and supercoiled circular double-stranded DNA (plasmids) was investigated using a phosphate buffer as a mobile phase at different velocities and column temperatures with a C1 column with very low-Packing Particle diameter as a stationary phase. It was shown that the two factors (temperature and velocity) constituted important parameters in the retention mechanism of plasmids and proteins in NEC. The protein was retained more than the plasmid. At all the temperatures (5, 10, 15, 20, 25 degrees C) the plasmid retention increased over the entire flow-rate range (0.02-1.8 ml/min). For the protein, the retention curve presented a decrease in the relative retention time until a critical value of the mobile phase flow-rate, followed by an increase. The transition between the two well known NEC methods, slalom chromatography and hydrodynamic chromatography was clearly visualized for proteins at the lowest temperature, but did not appear for plasmids due to their strong compact structure.
