Author: Samuel Avila
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Gas chromatography (GC) is an analytical chemistry tool used to determine the chemical composition of a gas sample by separating sample analytes as they travel through a GC column. Recent efforts have been made to understand and control gas chromatography separations with a negative thermal gradient on the column. The present work presents results from thermal gradient GC separations on two GC columns in different configurations (serpentine and radial) in a stainless-steel plate. Methods to fabricate the GC systems capable of isothermal, temperature programmed and thermal gradient separations are presented. Isothermal experimental data from the serpentine column were used to fit retention and dispersion parameters in a transport model that simulates GC separation for hydrocarbons C12-C14. Transport model simulated retention times and peak widths matched experimental values well for isothermal, temperature programmed and thermal gradient separations. The validated transport model was used to study the effect of static (not varying temporally) thermal gradients on GC separations with varying injection widths, injection band shapes and stationary phase thickness. Resolution results from different heating conditions were considered comparable if retention times for each analyte were within 5%. An optimal, static thermal gradient is shown to reduce analyte band spreading from axially-varying velocity gradients with resolution improvements over isothermal separations of up to 8% for analytes with similar retention factors. Static thermal gradients have a larger effect on fronting peak shape than tailing peak shape. Stationary phase distribution acts similar to a velocity gradient and can be corrected by a thermal gradient. Another transport model was created from isothermal experimental data on a commercial column for hydrocarbons C12-C20. An optimal, static thermal gradient does not improve resolution for all analyte pairs. An optimal, dynamic (varying tempo-rally) thermal gradient is created by uniformly increasing the temperature on an optimal, static thermal gradient. Improvements in resolution of up to 20% are achievable over temperature programmed GC separation. A dynamic thermal gradient can also correct for a poor sample injection by creating a temperature trap at the beginning of the column.
Effects of Static and Dynamic Thermal Gradients in Gas Chromatography
Author: Samuel Avila
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Gas chromatography (GC) is an analytical chemistry tool used to determine the chemical composition of a gas sample by separating sample analytes as they travel through a GC column. Recent efforts have been made to understand and control gas chromatography separations with a negative thermal gradient on the column. The present work presents results from thermal gradient GC separations on two GC columns in different configurations (serpentine and radial) in a stainless-steel plate. Methods to fabricate the GC systems capable of isothermal, temperature programmed and thermal gradient separations are presented. Isothermal experimental data from the serpentine column were used to fit retention and dispersion parameters in a transport model that simulates GC separation for hydrocarbons C12-C14. Transport model simulated retention times and peak widths matched experimental values well for isothermal, temperature programmed and thermal gradient separations. The validated transport model was used to study the effect of static (not varying temporally) thermal gradients on GC separations with varying injection widths, injection band shapes and stationary phase thickness. Resolution results from different heating conditions were considered comparable if retention times for each analyte were within 5%. An optimal, static thermal gradient is shown to reduce analyte band spreading from axially-varying velocity gradients with resolution improvements over isothermal separations of up to 8% for analytes with similar retention factors. Static thermal gradients have a larger effect on fronting peak shape than tailing peak shape. Stationary phase distribution acts similar to a velocity gradient and can be corrected by a thermal gradient. Another transport model was created from isothermal experimental data on a commercial column for hydrocarbons C12-C20. An optimal, static thermal gradient does not improve resolution for all analyte pairs. An optimal, dynamic (varying tempo-rally) thermal gradient is created by uniformly increasing the temperature on an optimal, static thermal gradient. Improvements in resolution of up to 20% are achievable over temperature programmed GC separation. A dynamic thermal gradient can also correct for a poor sample injection by creating a temperature trap at the beginning of the column.
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Gas chromatography (GC) is an analytical chemistry tool used to determine the chemical composition of a gas sample by separating sample analytes as they travel through a GC column. Recent efforts have been made to understand and control gas chromatography separations with a negative thermal gradient on the column. The present work presents results from thermal gradient GC separations on two GC columns in different configurations (serpentine and radial) in a stainless-steel plate. Methods to fabricate the GC systems capable of isothermal, temperature programmed and thermal gradient separations are presented. Isothermal experimental data from the serpentine column were used to fit retention and dispersion parameters in a transport model that simulates GC separation for hydrocarbons C12-C14. Transport model simulated retention times and peak widths matched experimental values well for isothermal, temperature programmed and thermal gradient separations. The validated transport model was used to study the effect of static (not varying temporally) thermal gradients on GC separations with varying injection widths, injection band shapes and stationary phase thickness. Resolution results from different heating conditions were considered comparable if retention times for each analyte were within 5%. An optimal, static thermal gradient is shown to reduce analyte band spreading from axially-varying velocity gradients with resolution improvements over isothermal separations of up to 8% for analytes with similar retention factors. Static thermal gradients have a larger effect on fronting peak shape than tailing peak shape. Stationary phase distribution acts similar to a velocity gradient and can be corrected by a thermal gradient. Another transport model was created from isothermal experimental data on a commercial column for hydrocarbons C12-C20. An optimal, static thermal gradient does not improve resolution for all analyte pairs. An optimal, dynamic (varying tempo-rally) thermal gradient is created by uniformly increasing the temperature on an optimal, static thermal gradient. Improvements in resolution of up to 20% are achievable over temperature programmed GC separation. A dynamic thermal gradient can also correct for a poor sample injection by creating a temperature trap at the beginning of the column.
Temperature-Programmed Gas Chromatography
Author: Leonid M. Blumberg
Publisher: John Wiley & Sons
ISBN: 3527632263
Category : Science
Languages : en
Pages : 363
Book Description
This book provides a comprehensive up-to-date overview of temperature-programmed gas chromatography (GC). The first part of the book introduces the reader to the basics concepts of GC, as well as the key properties of GC columns. The second part describes the mathematical and physical background of GC. In the third part, different aspects in the formation of a chromatogram are discussed, including retention times, peak spacing and peak widths. An invaluable reference for any chromatographer and analytical chemist, it provides all the answers to questions like: At what temperature does a solute elute in a temperature-programmed analysis? What is the value of the retention factor of eluting solute? How wide are the peaks? How large is the time distance between two peaks? How do all these parameters depend on the heating rate?
Publisher: John Wiley & Sons
ISBN: 3527632263
Category : Science
Languages : en
Pages : 363
Book Description
This book provides a comprehensive up-to-date overview of temperature-programmed gas chromatography (GC). The first part of the book introduces the reader to the basics concepts of GC, as well as the key properties of GC columns. The second part describes the mathematical and physical background of GC. In the third part, different aspects in the formation of a chromatogram are discussed, including retention times, peak spacing and peak widths. An invaluable reference for any chromatographer and analytical chemist, it provides all the answers to questions like: At what temperature does a solute elute in a temperature-programmed analysis? What is the value of the retention factor of eluting solute? How wide are the peaks? How large is the time distance between two peaks? How do all these parameters depend on the heating rate?
Thermal Gradient Characterization and Control in Micro-fabricated Gas Chromatography Systems
Author: Austin Richard Foster
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
Book Description
Temperature-Programmed Gas Chromatography
Author: Leonid M. Blumberg
Publisher: John Wiley & Sons
ISBN: 3527326421
Category : Science
Languages : en
Pages : 363
Book Description
This book provides a comprehensive up-to-date overview of temperature-programmed gas chromatography (GC). The first part of the book introduces the reader to the basics concepts of GC, as well as the key properties of GC columns. The second part describes the mathematical and physical background of GC. In the third part, different aspects in the formation of a chromatogram are discussed, including retention times, peak spacing and peak widths. An invaluable reference for any chromatographer and analytical chemist, it provides all the answers to questions like: At what temperature does a solute elute in a temperature-programmed analysis? What is the value of the retention factor of eluting solute? How wide are the peaks? How large is the time distance between two peaks? How do all these parameters depend on the heating rate?
Publisher: John Wiley & Sons
ISBN: 3527326421
Category : Science
Languages : en
Pages : 363
Book Description
This book provides a comprehensive up-to-date overview of temperature-programmed gas chromatography (GC). The first part of the book introduces the reader to the basics concepts of GC, as well as the key properties of GC columns. The second part describes the mathematical and physical background of GC. In the third part, different aspects in the formation of a chromatogram are discussed, including retention times, peak spacing and peak widths. An invaluable reference for any chromatographer and analytical chemist, it provides all the answers to questions like: At what temperature does a solute elute in a temperature-programmed analysis? What is the value of the retention factor of eluting solute? How wide are the peaks? How large is the time distance between two peaks? How do all these parameters depend on the heating rate?
High-speed Comprehensive Two Dimensional Gas Chromatography with Thermal Gradient Along the First Dimension Column
Author: Marie Thes M. Castro
Publisher:
ISBN:
Category :
Languages : en
Pages : 218
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 218
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 994
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 994
Book Description
Dynamics of Chromatography
Author: J. Calvin Giddings
Publisher: CRC Press
ISBN: 1420056468
Category : Science
Languages : en
Pages : 336
Book Description
This classic and bestselling landmark publication, originally published in 1965, examines the dynamic mechanisms, fundamental principles, and physical properties of various chromatographic procedures. It offers methods to characterize, identify, and predict chromatographic phenomena - providing strategies to select the most appropriate separation tools and techniques for specific applications in chemistry, physics, biology, and forensic and environmental science. Written by a world-renowned pioneer in the field, Dynamics of Chromatography contains many worked equations and real-world examples in gas and liquid chromatography. It includes numerous schematic figures for visualization of key concepts, introduces the means to control migration rate differences and zone spreading, and presents a detailed random-walk model for clarification of column processes. It also analyzes flow, diffusion, and kinetic events, stresses the link between theory and practice, and summarizes mathematical quantities and parameters.
Publisher: CRC Press
ISBN: 1420056468
Category : Science
Languages : en
Pages : 336
Book Description
This classic and bestselling landmark publication, originally published in 1965, examines the dynamic mechanisms, fundamental principles, and physical properties of various chromatographic procedures. It offers methods to characterize, identify, and predict chromatographic phenomena - providing strategies to select the most appropriate separation tools and techniques for specific applications in chemistry, physics, biology, and forensic and environmental science. Written by a world-renowned pioneer in the field, Dynamics of Chromatography contains many worked equations and real-world examples in gas and liquid chromatography. It includes numerous schematic figures for visualization of key concepts, introduces the means to control migration rate differences and zone spreading, and presents a detailed random-walk model for clarification of column processes. It also analyzes flow, diffusion, and kinetic events, stresses the link between theory and practice, and summarizes mathematical quantities and parameters.
Static Headspace-gas Chromatography
Author: Bruno Kolb
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 324
Book Description
This volume provides a description of the various techniques used for quantitative analysis, of the applications in pollution control (air, water and soil) and of the applications in food packaging and in food quality control. A brief theory of headspace sampling is also provided.
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 324
Book Description
This volume provides a description of the various techniques used for quantitative analysis, of the applications in pollution control (air, water and soil) and of the applications in food packaging and in food quality control. A brief theory of headspace sampling is also provided.
Design and Application of Thermal Gradient Programming Techniques for Use in Multidimensional Gas Chromatography-mass Spectrometry (MDGC-MS)
Author: Jesse Alberto Contreras
Publisher:
ISBN:
Category : Gas chromatography
Languages : en
Pages : 274
Book Description
Publisher:
ISBN:
Category : Gas chromatography
Languages : en
Pages : 274
Book Description
High Speed Gas Chromatography with Simultaneous Temperature Gradients in Time and Distance Along the Column
Author: Vivek Jain
Publisher:
ISBN:
Category :
Languages : en
Pages : 310
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 310
Book Description