The Development of Techniques for Complex Mixture Analysis by Means of Gas Chromatography/triple Quadrupole Mass Spectrometry PDF Download
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Author: Adam Jeremiah Schubert
Publisher:
ISBN:
Category : Analytical chemistry
Languages : en
Pages : 386
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Book Description
Author: Adam Jeremiah Schubert
Publisher:
ISBN:
Category : Analytical chemistry
Languages : en
Pages : 386
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Author: Luigi Mondello
Publisher: John Wiley & Sons
ISBN: 1118003454
Category : Technology & Engineering
Languages : en
Pages : 438
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Book Description
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.
Author: Brooke C. Reaser
Publisher:
ISBN:
Category :
Languages : en
Pages : 172
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Book Description
Gas chromatography is a powerful separation technique that alone, and when coupled with mass spectrometric detection, can provide detailed information regarding the chemical composition of complex mixtures. Advanced chemometric algorithms are often applied to the data generated from these gas chromatographic separations in order to glean additional meaningful information from large and complex data sets. This dissertation presents several research investigations conducted on the development, optimization, application and study of several chemometric algorithms applied to one- and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (TOFMS). The two-dimensional mass cluster method and principal component analysis (PCA) were applied to a non-targeted investigation of the stable-isotope incorporation of metabolites present in the metabolome of the methylotrophic bacteria Methylobacterium extorquens AM1 using gas chromatography time-of-flight mass spectrometry (GC-TOFMS). The area under the curve (AUC) of receiver operating characteristic (ROC) curves were used as quantitative metrics for the optimization of the tile-based Fisher ratio method using diesel fuel spiked with native and non-native analytes using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC – TOFMS). This optimized algorithm was then applied to a process analytical chemistry (PAC) investigation into the source of catalyst yield reduction in an industrial polymerization plant. Finally, a GC-TOFMS simulation-based study determined the chemometric limit of resolution for deconvoluting analytes using multivariate curve resolution alternating least squares (MCR-ALS) and compared the results to expected theory surrounding the probability of peak overlap.
Author: Fulton G. Kitson
Publisher: Academic Press
ISBN: 0080532322
Category : Science
Languages : en
Pages : 395
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Book Description
This guide provides, under one cover, a wealth of practical information designed to facilitate the effectiveness of the GC/MS user. Separation conditions for numerous compound types are provided along with derivatized and underivatized compounds. A section on how to interpret mass spectral data, an extensive correlation of ion masses and neutral losses with possible structures, and examples of mass spectra are provided to further aid structure determination. Also included are basic information on instrumentation, ionization methods, quantitation, tips on the operation of mass spectrometers, the best derivatization procedures for a variety of compound types, troubleshooting techniques, and a variety of other information found to be useful to the practicing user of GC/MS instrumentation. This guide would be immediately valuable to the novice as well as the experienced GC/MS user who may not have the breadth of experience covered in this book.Key Features* Condenses and organizes recent and essential information for new and experienced GC/MS users* Comprehensively indexed and referenced* Includes practical methods of analysis* Serves as a text reference for short practical courses on the subject
Author: Christopher E. Freye
Publisher:
ISBN:
Category :
Languages : en
Pages : 320
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Book Description
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.
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 780
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Book Description
Author: Michal Holcapek
Publisher: Elsevier
ISBN: 0128117338
Category : Technology & Engineering
Languages : en
Pages : 522
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Book Description
Handbook of Advanced Chromatography /Mass Spectrometry Techniques is a compendium of new and advanced analytical techniques that have been developed in recent years for analysis of all types of molecules in a variety of complex matrices, from foods to fuel to pharmaceuticals and more. Focusing on areas that are becoming widely used or growing rapidly, this is a comprehensive volume that describes both theoretical and practical aspects of advanced methods for analysis. Written by authors who have published the foundational works in the field, the chapters have an emphasis on lipids, but reach a broader audience by including advanced analytical techniques applied to a variety of fields. Handbook of Advanced Chromatography / Mass Spectrometry Techniques is the ideal reference for those just entering the analytical fields covered, but also for those experienced analysts who want a combination of an overview of the techniques plus specific and pragmatic details not often covered in journal reports. The authors provide, in one source, a synthesis of knowledge that is scattered across a multitude of literature articles. The combination of pragmatic hints and tips with theoretical concepts and demonstrated applications provides both breadth and depth to produce a valuable and enduring reference manual. It is well suited for advanced analytical instrumentation students as well as for analysts seeking additional knowledge or a deeper understanding of familiar techniques. - Includes UHPLC, HILIC, nano-liquid chromatographic separations, two-dimensional LC-MS (LCxLC), multiple parallel MS, 2D-GC (GCxGC) methodologies for lipids analysis, and more - Contains both practical and theoretical knowledge, providing core understanding for implementing modern chromatographic and mass spectrometric techniques - Presents chapters on the most popular and fastest-growing new techniques being implemented in diverse areas of research
Author: Mu Naushad
Publisher: CRC Press
ISBN: 1466591544
Category : Science
Languages : en
Pages : 480
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Book Description
Due to its high sensitivity and selectivity, liquid chromatography–mass spectrometry (LC–MS) is a powerful technique. It is used for various applications, often involving the detection and identification of chemicals in a complex mixture. Ultra Performance Liquid Chromatography Mass Spectrometry: Evaluation and Applications in Food Analysis presents a unique collection of up-to-date UPLC-MS/MS methods for the separation and quantitative determination of components, contaminants, vitamins, and aroma and flavor compounds in a wide variety of foods and food products. The book begins with an overview of the history, principles, and advancement of chromatography. It discusses the use of UHPLC techniques in food metablomics, approaches for analysis of foodborne carcinogens, and details of UPLC-MS techniques used for the separation and determination of capsaicinoids. Chapters describe the analysis of contaminants in food, including pesticides, aflatoxin, perfluorochemicals, and acrylamide, as well as potentially carcinogenic heterocyclic amines in cooked foods. The book covers food analysis for beneficial compounds, such as the determination of folate, vitamin content analysis, applications for avocado metabolite studies, virgin olive oil component analysis, lactose determination in milk, and analysis of minor components of cocoa and phenolic compounds in fruits and vegetables. With contributions by experts in interdisciplinary fields, this reference offers practical information for readers in research and development, production, and routing analysis of foods and food products.
Author: Sarah Elizabeth Prebihalo
Publisher:
ISBN:
Category :
Languages : en
Pages : 151
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Book Description
Comprehensive two-dimensional gas chromatography (GCxGC) coupled with time-of-flight mass spectrometry (TOFMS) is a powerful analytical technique capable of separating complex mixtures, providing valuable information about the chemical composition of samples. However, the inherent data density associated with three-dimensional data provides a unique challenge to analytical chemists. As a result, significant effort has been invested in utilizing advanced chemometrics to glean meaningful information about samples from large and complex data sets. Herein, this dissertation introduces several investigations conducted on optimizing separation conditions to be amenable to chemometric deconvolution algorithms as well as the development, study, and application of advanced chemometric techniques applied to GCxGC-TOFMS data. To begin, the metric trilinear deviation ratio (TDR) is utilized to study the impact of experimental parameters such as column selection and modulation period, PM, on the quantitative accuracy of parallel factor analysis (PARAFAC) deconvolution. TDR scales with increasing change in second dimension retention time, delta2tR, associated with pseudo-isothermal conditions on the second dimension, 2D, and quantitative accuracy decreases as TDR increases. Two column sets were utilized with varying film thickness on the first column, 1D, and each column set was studied using two PM for a total of 4 experiments. It was reported that using 1D columns with larger film thicknesses allows the analyst to employ a shorter PM, in turn lowering the delta2tR, leading to higher quantitative accuracy. Many GCxGC-TOFMS studies relate to identifying class distinguishing analytes and can be tedious when performed manually. Fortunately, the use of discovery-based chemometric tools such as principal component analysis (PCA) and Fisher ratio (F-ratio) analysis has increased in popularity as less time-intensive and automated techniques for untargeted analyses. To begin, this dissertation will investigate mass channel purity obtained via the tile-based F-ratio algorithm using diesel fuel spiked with non-native analytes using GCxGC-TOFMS. The F-ratio algorithm, considered a supervised discovery technique because class membership is known a priori, was first used to "discover" the spiked non-native analytes. Then, using a novel signal ratio (S-ratio) algorithm, the mass channel selectivity information output by the F-ratio method was studied using three statistical metrics: null distribution analysis, p-value, and lack-of-fit (LOF). The result of this investigation revealed that a mass channel has a high likelihood of being pure when its p-value and LOF are sufficiently low. Finally, F-ratio analysis was applied to a dataset including patients with an anterior cruciate ligament (ACL) injury to discover potential biomarkers of post-traumatic osteoarthritis (PTOA) post-injury. Standard F-ratios are calculated by the between class variance divided by the sum of the within-class variance, scaling up as the between class variance increases and the within-class variance remains sufficiently small. However, many biological studies involve significant biological variance (~30%) that may not be associated with disease state or injury severity, etc. Herein, the standard tile-based F-ratio algorithm was modified to use only the within-class variance associated with control samples. It was expected that the control class contained less within-class variance relative to the patient class, due to the expectation that some patient samples would be associated with increased severity of injury or the presence of coexisting conditions. Hit lists (metabolites discovered via F-ratio) from standard F-ratio and control-normalized F-ratio were studied and directly compared to establish a comprehensive metabolome of potential biomarkers for PTOA development post ACL injury. Reported in this dissertation is a discussion on the complementary nature of standard and control-normalized F-ratio, followed by demonstration of class distinguishing metabolites via PCA.
Author: Douglas M. Considine
Publisher: Springer Science & Business Media
ISBN: 1475769180
Category : Technology & Engineering
Languages : en
Pages : 3529
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Book Description
Advancements in science and engineering have occurred at a surprisingly rapid pace since the release of the seventh edition of this encyclopedia. Large portions of the reference have required comprehensive rewriting and new illustrations. Scores of new topics have been included to create this thoroughly updated eighth edition. The appearance of this new edition in 1994 marks the continuation of a tradition commenced well over a half-century ago in 1938 Van Nostrand's Scientific Encyclopedia, First Edition, was published and welcomed by educators worldwide at a time when what we know today as modern science was just getting underway. The early encyclopedia was well received by students and educators alike during a critical time span when science became established as a major factor in shaping the progress and economy of individual nations and at the global level. A vital need existed for a permanent science reference that could be updated periodically and made conveniently available to audiences that numbered in the millions. The pioneering VNSE met these criteria and continues today as a reliable technical information source for making private and public decisions that present a backdrop of technical alternatives.
