Thermal Gradient Characterization and Control in Micro-fabricated Gas Chromatography Systems PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Thermal Gradient Characterization and Control in Micro-fabricated Gas Chromatography Systems PDF full book. Access full book title Thermal Gradient Characterization and Control in Micro-fabricated Gas Chromatography Systems by Austin Richard Foster. Download full books in PDF and EPUB format.
Author: Austin Richard Foster
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
Get Book Here
Book Description
Author: Austin Richard Foster
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
Get Book Here
Book Description
Author: Carlos R. Vilorio
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
There has been substantial market demand for a portable Gas Chromatography (GC) system. Throughout the years, much progress has been made on fabricating a micro system that works as well as a benchtop system. Unfortunately, even though many substrates, channel types, channel widths, temperature control systems, and interface solutions have been attempted, existing versions of the micro-GC still fall short of the ideal. This thesis presents the design, fabrication, and testing of a silicon based micro-GC column that presents a solution for interfacing and heating of the chip. A polyimide resin is used to create a durable high temperature low thermal mass interface with the chip, while a silk screen method is demonstrated for easy printing of heaters. Chromatogram results are shown in both Temperature Program and Thermal Gradient runs.
Author: Wei-Cheng Tian
Publisher:
ISBN:
Category :
Languages : en
Pages : 474
Get Book Here
Book Description
Author: Samuel Avila
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
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.
Author: William L. Budde
Publisher:
ISBN:
Category : Gas chromatography
Languages : en
Pages : 48
Get Book Here
Book Description
Author: Anzi Wang
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 143
Get Book Here
Book Description
Although the airbath oven is a reliable heating method for gas chromatography (GC), resistive heating is needed for higher analytical throughput and on-site chemical analysis because of size, heating rate and power requirements. In the last thirty years, a variety of resistive heating methods were developed and implemented for both benchtop and portable GC systems. Although fast heating rates and low power consumption have been achieved, losses in column efficiency and resolution, complex construction processes and difficulties experienced in recovering damaged columns have also become problematic for routine use of resistively heated columns. To solve these problems, a new resistively heated column technique, which uses metal columns and self-insulated heating wires, was developed for capillary gas chromatography. With this method, the total thermal mass was significantly less than in commercial column assemblies. Temperature-programming using resistive heating was at least 10 times faster than with a conventional oven, while only consuming 1−5% of the power that an oven would use. Cooling a column from 350 °C to 25 °C with an air fan only required 1.5 min. Losses in column efficiency and peak capacity were negligible when compared to oven heating. The major trade-off was slightly worse run-to-run retention time deviations, which were still acceptable for most GC analyses. The resistively heated column bundle is highly suitable for fast GC separations and portable GC instruments.
Author: J.H. Sun
Publisher:
ISBN:
Category : Science
Languages : en
Pages :
Get Book Here
Book Description
Design, Modeling, Microfabrication and Characterization of the Micro Gas Chromatography Columns.
Author: Masoud Agah
Publisher:
ISBN:
Category :
Languages : en
Pages : 258
Get Book Here
Book Description
Author: J.H. Sun
Publisher:
ISBN: 9789535102984
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 570
Get Book Here
Book Description
