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Andreas Seidelmorgenstern - One of the best experts on this subject based on the ideXlab platform.
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theoretical investigation of thermal effects in an adiabatic Chromatographic Column using a lumped kinetic model incorporating heat transfer resistances
Industrial & Engineering Chemistry Research, 2018Co-Authors: Shamsul Qamar, Nadia Kiran, Talha Anwar, Sameena Bibi, Andreas SeidelmorgensternAbstract:A nonequilibrium nonisothermal lumped kinetic model (LKM) is analytically and numerically investigated to evaluate the effects of inherent temperature fluctuations in an adiabatic Chromatographic Column. The model comprises convection–diffusion partial differential equations quantifying mass and energy balances in the mobile phase coupled with differential and algebraic equations for mass and energy in the stationary phase. Besides two mass transfer coefficients, two heat transfer coefficients are involved in the model equations. The properties of the considered model are investigated for linear concentration and temperature dependencies of the equilibrium loadings. The Laplace transformation and Eigen decomposition techniques are utilized to solve the set of equations. These solutions are helpful for understanding, analyzing, and interpreting the propagation speeds and shapes of both concentration and thermal fronts migrating in Chromatographic Columns. The moment generating property of the Laplace domai...
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theoretical investigation of thermal effects in an adiabatic Chromatographic Column using a lumped kinetic model incorporating heat transfer resistances
Industrial & Engineering Chemistry Research, 2018Co-Authors: Shamsul Qamar, Nadia Kiran, Talha Anwar, Sameena Bibi, Andreas SeidelmorgensternAbstract:A nonequilibrium nonisothermal lumped kinetic model (LKM) is analytically and numerically investigated to evaluate the effects of inherent temperature fluctuations in an adiabatic Chromatographic Column. The model comprises convection–diffusion partial differential equations quantifying mass and energy balances in the mobile phase coupled with differential and algebraic equations for mass and energy in the stationary phase. Besides two mass transfer coefficients, two heat transfer coefficients are involved in the model equations. The properties of the considered model are investigated for linear concentration and temperature dependencies of the equilibrium loadings. The Laplace transformation and Eigen decomposition techniques are utilized to solve the set of equations. These solutions are helpful for understanding, analyzing, and interpreting the propagation speeds and shapes of both concentration and thermal fronts migrating in Chromatographic Columns. The moment generating property of the Laplace domai...
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theoretical analysis of the influence of forced and inherent temperature fluctuations in an adiabatic Chromatographic Column
Chemical Engineering Science, 2017Co-Authors: Shamsul Qamar, Fouzia Abdul Sattar, Iqra Batool, Andreas SeidelmorgensternAbstract:Abstract A linearized non-isothermal equilibrium dispersive model (EDM) of liquid chromatography is investigated to quantify unavoidable thermal effects in adiabatic Chromatographic Columns. The considered model contains convection-diffusion partial differential equations (PDEs) for mass and energy balances in the mobile phase coupled with an algebraic equation for adsorption isotherm. The solution process successively employ Laplace transformation and linear transformation steps to uncouple the governing set of coupled differential equations. The resulting uncoupled systems of ordinary differential equations are solved using an elementary solution technique. The solutions are very useful to understand the speeds and shapes of concentration and thermal fronts in Chromatographic Columns. The moment generating property of the Laplace domain solutions is utilized to derive analytical temporal moments of the concentration and temperature profiles. These moments are seen as useful to estimate unknown model parameters from measured profiles. For illustration several case studies of practical interest are provided. To evaluate the range of applicability of analytical solutions, selected results are compared with numerical results applying a high resolution finite volume scheme considering nonlinear isotherms.
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irreversible and reversible reactions in a liquid Chromatographic Column analytical solutions and moment analysis
Industrial & Engineering Chemistry Research, 2014Co-Authors: Shamsul Qamar, Andreas Seidelmorgenstern, Sameena Bibi, Farman U Khan, Munawar Shah, Shumaila JaveedAbstract:Reactive Chromatographic processes are investigated theoretically for irreversible A → B and reversible A ↔ B reactions. The models consist of two partial differential equations, accounting for each component convection, longitudinal dispersion, adsorption, and first-order chemical reactions. Analytical and numerical solutions of the models are needed for analyzing and optimizing the processes in the fixed-bed Column. Analytical solutions are obtained by means of Laplace transformation. Temporal moments are derived from the Laplace-transformed solutions. For validation, the high-resolution upwind finite volume scheme is applied to solve the model equations numerically. Several case studies are carried out, and the analytical solutions are compared with the numerical ones. The good agreement between solutions verify both the correctness of the analytical solutions and the accuracy of the suggested numerical scheme.
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theoretical investigation of the adsorption of a binary mixture in a Chromatographic Column using the nonlinear frequency response technique
Adsorption-journal of The International Adsorption Society, 2007Co-Authors: Milica Ilic, Andreas Seidelmorgenstern, Menka PetkovskaAbstract:The nonlinear frequency response of a Chromatographic Column for the adsorption of two dissolved components is analyzed using the concept of higher order frequency response functions (FRFs) which is based on the Volterra series and generalized Fourier transform. By applying this concept a nonlinear model of a system is replaced by an infinite series of the FRFs of the first, second, etc. order. The FRFs up to the third order are derived theoretically starting from the equilibrium-dispersive model, which is used for description of a Chromatographic Column, and applying the harmonic probing method. The functions that relate outlet concentration changes of each component to the corresponding inlet concentration changes are derived. At the inlet of a Chromatographic Column, it is considered: (a) the concentration change of one of the components keeping the concentration of the other component constant and (b) the concentration change of both components keeping their ratio constant. The FRFs are calculated numerically for different steady-state concentrations and relative mixture compositions. It has been found that, despite certain differences in initial conditions, the FRFs exhibit similar behavior. For higher frequencies, the amplitudes of the FRFs tend to zero and phases to −∞. In the low frequency range, which is of interest for investigation of equilibrium parameters, these functions have similar behavior, but tend to different asymptotic values. Correlations between coefficients of competitive adsorption isotherms, i.e. partial isotherm derivatives, and the derived FRFs are established. This theoretical result offers the potential to use the analysis of the nonlinear frequency response of a Chromatographic Column for estimation of competitive adsorption isotherms.
Shamsul Qamar - One of the best experts on this subject based on the ideXlab platform.
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theoretical investigation of thermal effects in an adiabatic Chromatographic Column using a lumped kinetic model incorporating heat transfer resistances
Industrial & Engineering Chemistry Research, 2018Co-Authors: Shamsul Qamar, Nadia Kiran, Talha Anwar, Sameena Bibi, Andreas SeidelmorgensternAbstract:A nonequilibrium nonisothermal lumped kinetic model (LKM) is analytically and numerically investigated to evaluate the effects of inherent temperature fluctuations in an adiabatic Chromatographic Column. The model comprises convection–diffusion partial differential equations quantifying mass and energy balances in the mobile phase coupled with differential and algebraic equations for mass and energy in the stationary phase. Besides two mass transfer coefficients, two heat transfer coefficients are involved in the model equations. The properties of the considered model are investigated for linear concentration and temperature dependencies of the equilibrium loadings. The Laplace transformation and Eigen decomposition techniques are utilized to solve the set of equations. These solutions are helpful for understanding, analyzing, and interpreting the propagation speeds and shapes of both concentration and thermal fronts migrating in Chromatographic Columns. The moment generating property of the Laplace domai...
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theoretical investigation of thermal effects in an adiabatic Chromatographic Column using a lumped kinetic model incorporating heat transfer resistances
Industrial & Engineering Chemistry Research, 2018Co-Authors: Shamsul Qamar, Nadia Kiran, Talha Anwar, Sameena Bibi, Andreas SeidelmorgensternAbstract:A nonequilibrium nonisothermal lumped kinetic model (LKM) is analytically and numerically investigated to evaluate the effects of inherent temperature fluctuations in an adiabatic Chromatographic Column. The model comprises convection–diffusion partial differential equations quantifying mass and energy balances in the mobile phase coupled with differential and algebraic equations for mass and energy in the stationary phase. Besides two mass transfer coefficients, two heat transfer coefficients are involved in the model equations. The properties of the considered model are investigated for linear concentration and temperature dependencies of the equilibrium loadings. The Laplace transformation and Eigen decomposition techniques are utilized to solve the set of equations. These solutions are helpful for understanding, analyzing, and interpreting the propagation speeds and shapes of both concentration and thermal fronts migrating in Chromatographic Columns. The moment generating property of the Laplace domai...
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Theoretical Investigation of Thermal Effects in an Adiabatic Chromatographic Column Using a Lumped Kinetic Model Incorporating Heat Transfer Resistances
2018Co-Authors: Shamsul Qamar, Nadia Kiran, Talha Anwar, Sameena Bibi, Andreas Seidel-morgensternAbstract:A nonequilibrium nonisothermal lumped kinetic model (LKM) is analytically and numerically investigated to evaluate the effects of inherent temperature fluctuations in an adiabatic Chromatographic Column. The model comprises convection–diffusion partial differential equations quantifying mass and energy balances in the mobile phase coupled with differential and algebraic equations for mass and energy in the stationary phase. Besides two mass transfer coefficients, two heat transfer coefficients are involved in the model equations. The properties of the considered model are investigated for linear concentration and temperature dependencies of the equilibrium loadings. The Laplace transformation and Eigen decomposition techniques are utilized to solve the set of equations. These solutions are helpful for understanding, analyzing, and interpreting the propagation speeds and shapes of both concentration and thermal fronts migrating in Chromatographic Columns. The moment generating property of the Laplace domain solutions is employed to obtain explicit analytical temporal moments of the concentration and energy profiles which provide instructive tools to analyze the properties of the model considered and to estimate unknown model parameters from measured transients. For illustration, several case studies are carried out by assuming realistic model parameters. The applicability range of the analytical solutions derived is assessed by comparing selected specific results with numerical results of a nonequilibrium and nonisothermal model by considering nonlinear adsorption isotherms
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theoretical analysis of the influence of forced and inherent temperature fluctuations in an adiabatic Chromatographic Column
Chemical Engineering Science, 2017Co-Authors: Shamsul Qamar, Fouzia Abdul Sattar, Iqra Batool, Andreas SeidelmorgensternAbstract:Abstract A linearized non-isothermal equilibrium dispersive model (EDM) of liquid chromatography is investigated to quantify unavoidable thermal effects in adiabatic Chromatographic Columns. The considered model contains convection-diffusion partial differential equations (PDEs) for mass and energy balances in the mobile phase coupled with an algebraic equation for adsorption isotherm. The solution process successively employ Laplace transformation and linear transformation steps to uncouple the governing set of coupled differential equations. The resulting uncoupled systems of ordinary differential equations are solved using an elementary solution technique. The solutions are very useful to understand the speeds and shapes of concentration and thermal fronts in Chromatographic Columns. The moment generating property of the Laplace domain solutions is utilized to derive analytical temporal moments of the concentration and temperature profiles. These moments are seen as useful to estimate unknown model parameters from measured profiles. For illustration several case studies of practical interest are provided. To evaluate the range of applicability of analytical solutions, selected results are compared with numerical results applying a high resolution finite volume scheme considering nonlinear isotherms.
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irreversible and reversible reactions in a liquid Chromatographic Column analytical solutions and moment analysis
Industrial & Engineering Chemistry Research, 2014Co-Authors: Shamsul Qamar, Andreas Seidelmorgenstern, Sameena Bibi, Farman U Khan, Munawar Shah, Shumaila JaveedAbstract:Reactive Chromatographic processes are investigated theoretically for irreversible A → B and reversible A ↔ B reactions. The models consist of two partial differential equations, accounting for each component convection, longitudinal dispersion, adsorption, and first-order chemical reactions. Analytical and numerical solutions of the models are needed for analyzing and optimizing the processes in the fixed-bed Column. Analytical solutions are obtained by means of Laplace transformation. Temporal moments are derived from the Laplace-transformed solutions. For validation, the high-resolution upwind finite volume scheme is applied to solve the model equations numerically. Several case studies are carried out, and the analytical solutions are compared with the numerical ones. The good agreement between solutions verify both the correctness of the analytical solutions and the accuracy of the suggested numerical scheme.
Haimei Zhou - One of the best experts on this subject based on the ideXlab platform.
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Micro Gas Chromatographic Column Embedded Elliptic Cylindrical Pillars with Low Inlet Pressure and Short Separation Time
2019 20th International Conference on Solid-State Sensors Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 2019Co-Authors: Xuelei Yang, Fei Feng, Bin Zhao, Bowen Tian, Haimei Zhou, Xinxin LiAbstract:In this paper, a serpentine micro gas Chromatographic (μGC) semi-packed Column embedded elliptic cylindrical pillars (ECPs-Column) with mesoporous silica as stationary phase was fabricated. Compared with μGC Column with cylindrical posts (CPs-Column), effective width of ECPs-Column was increased by 30%, which could achieve lower pressure drop and shorter separation time. Both μGC Columns had been used in experiments of separating alkanes (hexane, heptane, octane, nonane, decane). When the two kinds of μGC Columns yielded a minimum height equivalent to a theoretical plate (HETP) of octane, the inlet pressure of the ECPs-Column was reduced by 22.7% compared with the CPs-Column. Besides, this ECPs-Column had shortened the separation time under the same inlet pressure compared with the CPs-Column in the separation of alkanes.
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The Exploration of Silicon Nanowires as a Stationary Phase Support for Micro Gas Chromatographic Columns
2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS), 2019Co-Authors: Fei Feng, Xuelei Yang, Bin Zhao, Haimei Zhou, Xinxin LiAbstract:In this paper, silicon nanowires were innovatively used as a stationary phase support for micro-fabricated gas Chromatographic Column ( μGC colunm). The silicon nanowires were grown in-situ in the high aspect ratio microchannels of the μGC colunm, and polydimethylsiloxane (OV-101) was used as the stationary phase. It was demonstrated that the alkane mixture of C6-C10 was well separated by using the 2 m μGC colunm. The separation efficiency of the μGC colunm was as high as 23647 plates/m, which could be attributed to the large surface area of the silicon nanowires.
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improved separation of micro gas Chromatographic Column using mesoporous silica as a stationary phase support
Talanta, 2018Co-Authors: Fan Luo, Fei Feng, Bin Zhao, Lei Hou, Wenbin You, Haimei ZhouAbstract:Abstract In this paper, a novel and facile way to improve the separation of micro gas Chromatographic Column is presented which utilizes the mesoporous silica thin film as the stationary phase support. A serpentine semi-packed Column is fabricated based on a micro-electro-mechanical system (MEMS) technology and polydimethylsiloxane is used as the stationary phase. The Chromatographic resolution of C6-C7 increases from unseparated to 7.44 after depositing mesoporous silica thin film as the stationary phase support in the separation of a mixture of heavy hydrocarbons (C6-C10), and the separation efficiency is as high as 9290 plates/m. Meanwhile, in the separation of a mixture of benzene series (gas mixtures of benzene, toluene and paraxylene), the Chromatographic resolution of benzene and toluene can also be increased by 483%. Those outstanding results indicate that using the mesoporous silica as the stationary phase support is an effective way to improve the separation efficiency of the gas Chromatographic Column.
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a micro gas Chromatographic Column with embedded elliptic cylindrical posts
Journal of Chromatography A, 2018Co-Authors: Bowen Tian, Fei Feng, Bin Zhao, Haimei Zhou, Fan Luo, Wu YanhongAbstract:In this paper, a novel embeded elliptic cylindrical posts (ECPs) with large surface area and wide effective width, which could support more stationary phase and decrease the pressure drop, is applied on the micro-fabricated gas Chromatographic (μGC) Column. Compared with μGC Column with cylindrical posts (CPs), the surface area and effective width of μGC Column with ECPs are increased by 29% and 30%. Separation experiments are performed under the same head pressure at Column inlet: in experiments of separating mixture 1, the Column efficiency of the μGC Column with ECPs for C9 has a 76% improvement, and the separation resolution between C8 and C9 also has a 34% improvement; in experiments of separating mixture 2, seven kinds of analytes can be identified by the μGC Column with ECPs less than ten minutes, while, only six kinds can be identified by the μGC Column with CPs in almost the same time. In detail, the Column efficiency of the μGC Column with ECPs for toluene has a 129% improvement, and the separation resolution between benzene and toluene also has a 56.4% improvement. Hence, the μGC Column with the inner structures of ECPs is a valid means to improve Column efficiency and resolution in a lower pressure drop.
Brian D. Kelley - One of the best experts on this subject based on the ideXlab platform.
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high throughput screening of Chromatographic separations i method development and Column modeling
Biotechnology and Bioengineering, 2008Co-Authors: Jonathan Coffman, Jack F. Kramarczyk, Brian D. KelleyAbstract:The development of purification processes for protein biopharmaceuticals is challenging due to compressed development timelines, long experimental times, and the need to survey a large parameter space. Typical methods for development of a chromatography step evaluate several dozen Chromatographic Column runs to optimize the conditions. An efficient batch-binding method of screening Chromatographic purification conditions in a 96-well format with a robotic liquid-handling system is described and evaluated. The system dispenses slurries of Chromatographic resins into filter plates, which are then equilibrated, loaded with protein, washed and eluted. This paper evaluates factors influencing the performance of this high-throughput screening technique, including the reproducibility of the aliquotted resin volume, the contact time of the solution and resin during mixing, and the volume of liquid carried over in the resin bed after centrifugal evacuation. These factors led to the optimization of a batch-binding technique utilizing either 50 or 100 µL of resin in each well, the selection of an industrially relevant incubation time of 20 min, and the quantitation of the hold-up volume, which was as much as one quarter of the total volume added to each well. The results from the batch-binding method compared favorably to Chromatographic Column separation steps for a cGMP protein purification process utilizing both hydrophobic interaction and anion-exchange steps. These high-throughput screening tools can be combined with additional studies on the kinetics and thermodynamics of protein–resin interactions to provide fundamental information which is useful for defining and optimizing Chromatographic separations steps. Biotechnol. Bioeng. 2008;100: 605–618. © 2008 Wiley Periodicals, Inc.
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High-throughput screening of Chromatographic separations: I. method development and Column modeling
Biotechnology and Bioengineering, 2008Co-Authors: Jonathan L. Coffman, Jack F. Kramarczyk, Brian D. KelleyAbstract:The development of purification processes for protein biopharmaceuticals is challenging due to compressed development timelines, long experimental times, and the need to survey a large parameter space. Typical methods for development of a chromatography step evaluate several dozen Chromatographic Column runs to optimize the conditions. An efficient batch-binding method of screening Chromatographic purification conditions in a 96-well format with a robotic liquid-handling system is described and evaluated. The system dispenses slurries of Chromatographic resins into filter plates, which are then equilibrated, loaded with protein, washed and eluted. This paper evaluates factors influencing the performance of this high-throughput screening technique, including the reproducibility of the aliquotted resin volume, the contact time of the solution and resin during mixing, and the volume of liquid carried over in the resin bed after centrifugal evacuation. These factors led to the optimization of a batch-binding technique utilizing either 50 or 100 microL of resin in each well, the selection of an industrially relevant incubation time of 20 min, and the quantitation of the hold-up volume, which was as much as one quarter of the total volume added to each well. The results from the batch-binding method compared favorably to Chromatographic Column separation steps for a cGMP protein purification process utilizing both hydrophobic interaction and anion-exchange steps. These high-throughput screening tools can be combined with additional studies on the kinetics and thermodynamics of protein-resin interactions to provide fundamental information which is useful for defining and optimizing Chromatographic separations steps.
Fei Feng - One of the best experts on this subject based on the ideXlab platform.
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Micro Gas Chromatographic Column Embedded Elliptic Cylindrical Pillars with Low Inlet Pressure and Short Separation Time
2019 20th International Conference on Solid-State Sensors Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), 2019Co-Authors: Xuelei Yang, Fei Feng, Bin Zhao, Bowen Tian, Haimei Zhou, Xinxin LiAbstract:In this paper, a serpentine micro gas Chromatographic (μGC) semi-packed Column embedded elliptic cylindrical pillars (ECPs-Column) with mesoporous silica as stationary phase was fabricated. Compared with μGC Column with cylindrical posts (CPs-Column), effective width of ECPs-Column was increased by 30%, which could achieve lower pressure drop and shorter separation time. Both μGC Columns had been used in experiments of separating alkanes (hexane, heptane, octane, nonane, decane). When the two kinds of μGC Columns yielded a minimum height equivalent to a theoretical plate (HETP) of octane, the inlet pressure of the ECPs-Column was reduced by 22.7% compared with the CPs-Column. Besides, this ECPs-Column had shortened the separation time under the same inlet pressure compared with the CPs-Column in the separation of alkanes.
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The Exploration of Silicon Nanowires as a Stationary Phase Support for Micro Gas Chromatographic Columns
2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS), 2019Co-Authors: Fei Feng, Xuelei Yang, Bin Zhao, Haimei Zhou, Xinxin LiAbstract:In this paper, silicon nanowires were innovatively used as a stationary phase support for micro-fabricated gas Chromatographic Column ( μGC colunm). The silicon nanowires were grown in-situ in the high aspect ratio microchannels of the μGC colunm, and polydimethylsiloxane (OV-101) was used as the stationary phase. It was demonstrated that the alkane mixture of C6-C10 was well separated by using the 2 m μGC colunm. The separation efficiency of the μGC colunm was as high as 23647 plates/m, which could be attributed to the large surface area of the silicon nanowires.
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improved separation of micro gas Chromatographic Column using mesoporous silica as a stationary phase support
Talanta, 2018Co-Authors: Fan Luo, Fei Feng, Bin Zhao, Lei Hou, Wenbin You, Haimei ZhouAbstract:Abstract In this paper, a novel and facile way to improve the separation of micro gas Chromatographic Column is presented which utilizes the mesoporous silica thin film as the stationary phase support. A serpentine semi-packed Column is fabricated based on a micro-electro-mechanical system (MEMS) technology and polydimethylsiloxane is used as the stationary phase. The Chromatographic resolution of C6-C7 increases from unseparated to 7.44 after depositing mesoporous silica thin film as the stationary phase support in the separation of a mixture of heavy hydrocarbons (C6-C10), and the separation efficiency is as high as 9290 plates/m. Meanwhile, in the separation of a mixture of benzene series (gas mixtures of benzene, toluene and paraxylene), the Chromatographic resolution of benzene and toluene can also be increased by 483%. Those outstanding results indicate that using the mesoporous silica as the stationary phase support is an effective way to improve the separation efficiency of the gas Chromatographic Column.
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a micro gas Chromatographic Column with embedded elliptic cylindrical posts
Journal of Chromatography A, 2018Co-Authors: Bowen Tian, Fei Feng, Bin Zhao, Haimei Zhou, Fan Luo, Wu YanhongAbstract:In this paper, a novel embeded elliptic cylindrical posts (ECPs) with large surface area and wide effective width, which could support more stationary phase and decrease the pressure drop, is applied on the micro-fabricated gas Chromatographic (μGC) Column. Compared with μGC Column with cylindrical posts (CPs), the surface area and effective width of μGC Column with ECPs are increased by 29% and 30%. Separation experiments are performed under the same head pressure at Column inlet: in experiments of separating mixture 1, the Column efficiency of the μGC Column with ECPs for C9 has a 76% improvement, and the separation resolution between C8 and C9 also has a 34% improvement; in experiments of separating mixture 2, seven kinds of analytes can be identified by the μGC Column with ECPs less than ten minutes, while, only six kinds can be identified by the μGC Column with CPs in almost the same time. In detail, the Column efficiency of the μGC Column with ECPs for toluene has a 129% improvement, and the separation resolution between benzene and toluene also has a 56.4% improvement. Hence, the μGC Column with the inner structures of ECPs is a valid means to improve Column efficiency and resolution in a lower pressure drop.
