Basic Multidimensional Gas Chromatography

Basic Multidimensional Gas Chromatography
Author:
Publisher: Academic Press
Total Pages: 332
Release: 2020-03-20
Genre: Science
ISBN: 0128137460

Basic Multidimensional Gas Chromatography is aimed at the next generation of multidimensional gas chromatography users who will require basic training in the fundamentals of both GC and GCxGC. This book fills the current need for an inexpensive, straightforward guidebook to get new users started. It will help new users determine when to add or purchase a multidimensional system and teach them to optimize and maximize the capability of each system. Readers will also learn to select specific modes for each portion of a multidimensional analysis. This ideal resource is a concise, hard-hitting text that provides the facts needed to get users up and running. Provides a comprehensive and fundamental introduction to multidimensional gas chromatography Assists readers in determining when to add or purchase a multidimensional system Explains how a given system can be used to its maximum capacity and how users should choose specific modes for different portions of multidimensional analysis

Characterization of Odorant Patterns by Comprehensive Two-Dimensional Gas Chromatography

Characterization of Odorant Patterns by Comprehensive Two-Dimensional Gas Chromatography
Author:
Publisher: Elsevier
Total Pages: 444
Release: 2022-02-16
Genre: Science
ISBN: 0323988822

The volume has as primary focus multidimensional gas chromatography (heart-cutting systems, comprehensive 2D-GC systems and hybrid solutions) and its characteristic features for in depth investigation of complex fractions of odor-active volatiles. Contributions, from outstanding researchers in the field from Academia and industry, cover fundamentals aspects on the physiology of olfaction, the strategies to identify key-odorants from the bulk of detectable volatiles (sensomics), the principles of operation of multidimensional analytical platforms (i.e., comprehensive two-dimensional gas chromatography – GC×GC; heart-cut 2D-GC, hybrid systems), and the fundamental role of mass spectrometry in providing reliable and informative data. Insights on new systems design and configurations are also provided, including sample preparation and data processing strategies, as important steps of the whole analytical process. Real-world examples cover food volatiles, complex aroma mixtures, odors emitted from industrial plants, volatiles of interest in forensic and medical applications. - Providing insights on fundamental aspects and advances in analytical platforms design and work-flows implementation for volatiles and odorants patterns detection in key-application areas - Up-dates on the most modern and advanced solutions to isolate, detect and characterize complex odorant patterns by multidimensional analytical techniques - Critical overview on main application areas where odors have a key-information role: food aroma and flavor industry, industrial environments, forensic and clinical applications

Advanced Gas Chromatography in Food Analysis

Advanced Gas Chromatography in Food Analysis
Author: Peter Q Tranchida
Publisher: Royal Society of Chemistry
Total Pages: 492
Release: 2019-10-30
Genre: Science
ISBN: 1788011279

Gas chromatography is widely used in applications involving food analysis. Typical applications pertain to the quantitative and/or qualitative analysis of food composition, natural products, food additives, and flavour and aroma components. Providing an up-to-date look at the significant advances in the technology, this book includes details on novel sample preparation processes; conventional, high-speed multidimensional gas chromatography systems, including preparative instrumentation; gas chromatography–olfactometry principles; and, finally, chemometrics principles and applications in food analysis. Aimed at providing the food researcher or analyst with detailed analytical information related to advanced gas chromatography technologies, this book is suitable for professionals and postgraduate students learning about the technique in the food industry and research.

Development of Instrumental and Chemometric Techniques for the Analysis of Complex Samples Via Multi-dimensional Gas Chromatography

Development of Instrumental and Chemometric Techniques for the Analysis of Complex Samples Via Multi-dimensional Gas Chromatography
Author: Christopher E. Freye
Publisher:
Total Pages: 320
Release: 2018
Genre:
ISBN:

A combination of four instrumental systems and five chemometric methods are shown to improve the efficiency and resolving power (i.e. peak capacity/ peak capacity production) of multi-dimensional gas chromatography (MDGC) as well as provide straightforward, easily interpretable chemical information. Implementation of a high speed pulse flow valve for two-dimensional gas chromatography (GC × GC) is shown to provide ultra-fast modulation with modulation periods (P[subscript]M) as short as 50 ms. Using a commercially available pulse flow valve, this injection technique performs a combination of vacancy chromatography and frontal analysis, whereby each pulse disturbance in the analyte concentration profile as it exits the first column (1D) results in data that is readily converted into a second separation (2D). A three-step process converts the raw data into a format analogous to a GC × GC separation, incorporating signal differentiation, baseline correction and conversion to a GC × GC chromatogram representation. For a P[subscript]M of 250 ms, the apparent peak width on the 2D, 2W[subscript]b, ranged from 12 to 45 ms producing a 2D peak capacity, 2n[subscript]c, of ~ 10, and the total peak capacity, n[subscript]c,2[subscript]D, was 4300 or a peak capacity production of 650 peaks/min. Next, the use of a high temperature diaphragm valve as a modulator for GC × GC facilitated separation temperatures up to 325 °C. Previous diaphragm valve technology limited use to 175 °C if the valve was mounted in the oven or to 265 °C if the valve was face mounted on the outside of the oven. A 44-component mixture was evaluated and the diaphragm valve created narrow, reproducible peaks on the 2D dimension leading to a peak capacity production of 300 peaks/min and had minimal retention time shifting on the 1D and 2D dimensions. In addition, the high temperature diaphragm valve was shown to increase the detection sensitivity by ~8 times compared to one-dimensional gas chromatography due to zone compression. Furthermore, the high temperature diaphragm valve was proven to be compatible with time-of-flight mass spectrometry (TOFMS). Finally a combination of the high temperature diaphragm valve and pulse flow valve yielded a three-dimensional gas chromatography system (GC3) that had a peak capacity production of 1000 peaks/min which is a ~5 times increase in efficiency compared to other GC3 systems. Investigation of novel chemometric techniques for the analysis of GC × GC is shown to be beneficial in extracting useful chemical information from complicated samples. Kerosene-based rocket fuels were analyzed via a GC × GC – FID system that implemented a high temperature diaphragm valve as a modulator. Using leave-one-out cross validation (LOOCV), the summed GC × GC – FID signal of three compound-class selective 2D regions (alkanes, cycloalkanes, and aromatics) was regressed against previously measured ASTM derived values. Additionally, a more detailed partial least squares (PLS) analysis was performed on compound classes (n-alkanes, iso-alkanes, mono-, di-, and tri-cycloalkanes, and aromatics) as well as the physical properties previously determined by ASTM methods (such as net heat of combustion, hydrogen content, density, kinematic viscosity, sustained boiling temperature and vapor rise temperature). The resulting models had low root mean square errors of cross validation (RMSECV) and had similar outcomes to previously reported results using a GC × GC – TOFMS. Using the information gained from the study, a more extensive study of predicting four physical properties (e.g., viscosity, heat of combustion, hydrogen content, and density) was undertaken using 74 different kerosene-based fuels. Highly reliable PLS models were developed that related chemical composition obtained via GC × GC – TOFMS to fuel properties obtained via ASTM methods. The PLS prediction of the four physical properties (e.g., viscosity, heat of combustion, hydrogen content, and density) had relatively low errors of RMSECV values of 0.0434, 38.1, 0.112, and 0.0037, respectively. Investigation of the linear regression vectors (LRVs) indicate the relationship between the chemical composition and physical properties enabling the chemical compositions of fuels to be altered to meet certain industrial specifications. Using a similar fuel set comprised of 36 kerosene-based fuels, the thermal stability was evaluated using a novel instrument, CRAFTI (Compact Rapid Assessment of Fuel Thermal Integrity). Using a chemometrics-based feature discovery algorithim, the chemical information obtained via GC × GC – TOFMS was correlated to the thermal integrity data. Certain forms of carbon that were deposited within the test article of the CRAFTI instrument were found to strongly correlate with increased backpressure and some of the more prevalent compounds were identified. Next, tile-based Fisher ratio (F-ratio) analysis was applied to tandem ionization time-of-flight mass spectrometry (TI – TOFMS) in order to enhance discovery-based analyses. A hard ionization energy (70 eV) and soft ionization energy (14 eV) were collected concurrently, and the discovery of 12 analytes spiked in diesel fuel was shown to be improved when the two ionization energies were used in tandem resulting in a higher discovery rate while also lowering the number of false positives. Using parallel factor analysis (PARAFAC) the analytes that were “discovered” were deconvoluted in order to obtain their identification via match values. Lastly, the limit of detection (LOD) and limit of quantification (LOQ) were improved by a novel integration method. Signal to noise (S/N) enhancement was theoretically studied using simulations and both the LOD and LOQ can be lowered by a factor of 3. When compared to the two-step, a commonly applied method for quantifying one-dimensional and two-dimensional, the integration method resulted in more accurate and precise measurements at low S/N.

Analytical Reaction Gas Chromatography

Analytical Reaction Gas Chromatography
Author: Viktor G. Berezkin
Publisher: Springer Science & Business Media
Total Pages: 199
Release: 2012-12-06
Genre: Science
ISBN: 1468407090

The most universal and effective method for the analysis of complex multicomponent mixtures of volatile substances is gas chromatography. However, there are a number of limitations asso ciated with the classical variation of this technique which retard its development and the further expansion of its application: 1) the identification of the components of a complex mix ture of unknown composition is in itself a complex and difficult problem, unless the homologous series of the component to be identified is known; 2) the overlapping of chromatographic peaks for several compounds makes it difficult, and in a number of cases impossible, to carry out qualitative and quantitative analysis of these components, and leads to the necessity of using several columns of different polarities or to the use of columns with very high efficiency; 3) the direct analysis of unstable and nonvolatile compounds is impossible; 4) the difficulty of quantitative chromatographic analysis using thermal conductivity detectors increases with the necessity of determining individual response (calibration) factors; the insensitivity of the flame ionization detector to a number of substances (inorganic gases) leads to the necessity of introducing additional operations (prelimi nary concentration of trace components) in connection with thermal conductivity detectors. vii viii FOREWORD The directed use of chemical conversion of the compounds analyzed usually makes it possible to remove the limitations cited above.

Advances in Feature Selection in One- and Two-dimensional Gas Chromatography with Mass Spectrometry

Advances in Feature Selection in One- and Two-dimensional Gas Chromatography with Mass Spectrometry
Author: Kelsey Leigh Berrier
Publisher:
Total Pages: 223
Release: 2020
Genre:
ISBN:

One- and two-dimensional gas chromatography coupled with mass spectrometry provides an enormous amount of quantitative data describing the chemical composition of complex samples. Besides quantification and identification of analytes, common analysis goals include classifying samples or predicting sample properties based upon the chemical information contained in the chromatographic data. The chemometric modeling techniques used to accomplish these goals often benefit from the removal of redundant or irrelevant chromatographic variables, which is achieved by feature selection. This dissertation presents several research studies detailing advances in and applications of feature selection applied to one- and two-dimensional gas chromatography with mass spectrometric detection. The two-dimensional mass cluster method was evaluated as a peak detection algorithm using simulations of gas chromatography coupled with time-of-flight mass spectrometry (GC-TOFMS) data under varying sample and separation complexity. An unsupervised feature selection method based on variance thresholding was applied to simulated GC-MS chromatograms and a previously studied yeast metabolome dataset. A successful application of partial least squares (PLS) regression analysis to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-TOFMS) for the prediction of bulk physical properties of kerosene-based fuels is included to demonstrate a case where feature selection was not required. Finally, supervised feature selection was implemented on GCxGC-TOFMS data of rocket fuels to aid in the prediction of fuel thermal integrity by PLS.

Fire Debris Analysis

Fire Debris Analysis
Author: Eric Stauffer
Publisher: Academic Press
Total Pages: 683
Release: 2007-12-10
Genre: Law
ISBN: 0080556264

The study of fire debris analysis is vital to the function of all fire investigations, and, as such, Fire Debris Analysis is an essential resource for fire investigators. The present methods of analysis include the use of gas chromatography and gas chromatography-mass spectrometry, techniques which are well established and used by crime laboratories throughout the world. However, despite their universality, this is the first comprehensive resource that addresses their application to fire debris analysis.Fire Debris Analysis covers topics such as the physics and chemistry of fire and liquid fuels, the interpretation of data obtained from fire debris, and the future of the subject. Its cutting-edge material and experienced author team distinguishes this book as a quality reference that should be on the shelves of all crime laboratories. - Serves as a comprehensive guide to the science of fire debris analysis - Presents both basic and advanced concepts in an easily readable, logical sequence - Includes a full-color insert with figures that illustrate key concepts discussed in the text

Comprehensive Chromatography in Combination with Mass Spectrometry

Comprehensive Chromatography in Combination with Mass Spectrometry
Author: Luigi Mondello
Publisher: John Wiley & Sons
Total Pages: 438
Release: 2011-08-24
Genre: Technology & Engineering
ISBN: 1118003454

This book provides a detailed description of various multidimensional chromatographic separation techniques. The editor first provides an introduction to the area and then dives right into the various complex separation techniques. While still not used routinely comprehensive chromatography techniques will help acquaint the readers with the fundamentals and possible benefits of multi-dimensional separations coupled with mass spectrometry. The topics include a wide range of material that will appease all interested in either entering the field of multidimensional chromatography and those looking to gain a better understanding of the topic.

Comprehensive Two Dimensional Gas Chromatography

Comprehensive Two Dimensional Gas Chromatography
Author: Lourdes Ramos
Publisher: Elsevier
Total Pages: 324
Release: 2009-07-22
Genre: Science
ISBN: 008093269X

The book reviews the basic concepts and highlights the most relevant advances and developments that have taken place in the field of comprehensive two dimensional gas chromatography (GC x GC) since its introduction in 1991. The several instrumental and technical approaches assayed and developed during these seventeen years and that have contributed to the development of this powerful separation technique and to its increasing application in many areas is explained and comprehensively illustrated through a number of chapters devoted these specific topics. More specialized aspects of the technique, including theoretical aspects, modelization of the chromatographic process, software developments, and alternative couplings is also covered. Finally, special attention is paid to data treatment, for both qualitative and quantitative analysis. This book will be a practical resource that will explain from basic to specialized concepts of GC x GC and will show the current state-of-the-art and discuss future trends of this technique. - Outlines basic concepts and principles of GCxGC technique for non-specialists to apply the technique to their research - Provides detailed descriptions of recent technical advances and serves as an instructional guide in latest applications in GCxGC - Sets the scene for possible future development and alternative new applications of technique