High Temperature Gas Chromatography of Aromatic Hydrocarbons PDF Download
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Author: Robert A. Baxter
Publisher:
ISBN:
Category : Gas chromatography
Languages : en
Pages : 34
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Author: Robert A. Baxter
Publisher:
ISBN:
Category : Gas chromatography
Languages : en
Pages : 34
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Author:
Publisher:
ISBN:
Category : Polycyclic aromatic hydrocarbons
Languages : en
Pages : 500
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Author: Walter L. Zielinski
Publisher: CRC Press
ISBN:
Category : Science
Languages : en
Pages : 256
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Book Description
This volume covers the world's literature between 1970 and 1980 and addresses the wide diversity of hydrocarbons structures, the basic operating components of the gas chromatographic system and their control for optimizing separations. It includes numerous chromatograms depicting separations of various hydrocarbon classes and features three major sections on hydrocarbon analysis with respect to general ap-plication, specific studies, and special techniques. The properties and characteristics of and studies employing the broad spectrum of available liquid phases and absorbents as separating media and studies reporting retention data for the different hydrocarbon classes are described. The text provides 45 comprehensive retention tables containing several thousand indices in a standardized retention index format.
Author: Mohamed Elrutb
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Factors affecting the detennination of PAHs by capillary GC/MS were studied. The effect of the initial column temperature and the injection solvent on the peak areas and heights of sixteen PAHs, considered as priority pollutants, USillg crosslinked methyl silicone (DB!) and 5% diphenyl, 94% dimethyl, 1% vinyl polysiloxane (DBS) columns was examined. The possibility of using high boiling point alcohols especially butanol, pentanol, cyclopentanol, and hexanol as injection solvents was investigated. Studies were carried out to optimize the initial column temperature for each of the alcohols. It was found that the optimum initial column temperature is dependent on the solvent employed. The peak areas and heights of the PAHs are enhanced when the initial column temperature is 10-20 c above the boiling point of the solvent using DB5 column, and the same or 10 C above the boiling point of the solvent using DB1 column. Comparing the peak signals of the PAHs using the alcohols, p-xylene, n-octane, and nonane as injection solvents, hexanol gave the greatest peak areas and heights of the PAHs particularly the late-eluted peaks. The detection limits were at low pg levels, ranging from 6.0 pg for fluorene t9 83.6 pg for benzo(a)pyrene. The effect of the initial column temperature on the peak shape and the separation efficiency of the PARs was also studied using DB1 and DB5 columns. Fronting or splitting of the peaks was obseIVed at very low initial column temperature. When high initial column temperature was used, tailing of the peaks appeared. Great difference between DB! and.DB5 columns in the range of the initial column temperature in which symmetrical.peaks of PAHs can be obtained is observed. Wider ranges were shown using DB5 column. Resolution of the closely-eluted PAHs was also affected by the initial column temperature depending on the stationary phase employed. In the case of DB5, only the earlyeluted PAHs were affected; whereas, with DB1, all PAHs were affected. An analytical procedure utilizing solid phase extraction with bonded phase silica (C8) cartridges combined with GC/MS was developed to analyze PAHs in water as an alternative method to those based on the extraction with organic solvent. This simple procedure involved passing a 50 ml of spiked water sample through C8 bonded phase silica cartridges at 10 ml/min, dried by passing a gentle flow of nitrogen at 20 ml/min for 30 sec, and eluting the trapped PAHs with 500 Jll of p-xylene at 0.3 ml/min. The recoveries of PAHs were greater than 80%, with less than 10% relative standard deviations of nine determinations. No major contaminants were present that could interfere with the recognition of PAHs. It was also found that these bonded phase silica cartridges can be re-used for the extraction of PAHs from water.
Author: Milton Lee
Publisher: Elsevier
ISBN: 0323149030
Category : Science
Languages : en
Pages : 475
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Book Description
Analytical Chemistry of Polycyclic Aromatic Compounds focuses on the chemical and physical properties of the polycyclic aromatic compounds, critically evaluating various chromatographic and spectroscopic methods. This book discusses how gas chromatography and high-performance liquid chromatography can be both competitive and complementary analytical methods. Ancillary techniques of both are emphasized for the structural elucidation of individual polycyclic aromatic compounds in complex mixtures. The merits of spectroscopic methods in both structural work and quantitation are also described. This text likewise provides background information concerning the chemistry, occurrence, and toxicology of polycyclic aromatic compounds, including the isolation of polycyclic aromatic compounds from a wide variety of materials and matrices. This publication is recommended to scientists involved with the study of polycyclic aromatic compounds, analysts who need to acquire routine data, and individuals charged with formulating environmental policies and drafting regulations.
Author: Xing-Fang Li
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Factors involved in the determination of PAHs (16 priority PAHs as an example) and PCBs (10 PCB congeners, representing 10 isomeric groups) by capillary gas chromatography coupled with mass spectrometry (GC/MS, for PAHs) and electron capture detection (GC/ECD , for PCBs) were studied, with emphasis on the effect of solvent. Having various volatilities and different polarities, solvent studied included dichloromethane, acetonitrile, hexan e, cyclohexane, isooctane, octane, nonane, dodecane, benzene, toluene, p-xylene, o-xylene, and mesitylene. Temperatures of the capillary column, the injection port, the GC/MS interface, the flow rates of carrier gas and make-up gas, and the injection volume were optimized by one factor at a time method or simplex optimization method. Under the optimized conditions, both peak height and peak area of 16 PAHs, especially the late-eluting PAHs, were significantly enhanced (1 to 500 times) by using relatively higher boiling point solvents such as p-xylene and nonane, compared with commonly used solvents like benzene and isooctane. With the improved sensitivity, detection limits of between 4.4 pg for naphthalene and 30.8 pg for benzo[g,h,i]perylene were obtained when p-xylene was used as an injection solvent. Effect of solvent on peak shape and peak intensity were found to be greatly dependent on temperature parameters, especially the initial temperature of the capillary column. The relationship between initial temperature and shape of peaks from 16 PAHs and 10 PCBs were studied and compared when toluene, p-xylene, isooctane, and nonane were used as injection solvents. If a too low initial temperature was used, fronting or split of peaks was observed. On the other hand, peak tailing occurred at a too high initial column temperature. The optimum initial temperature, at which both peak fronting and tailing were avoided and symmetrical peaks were obtained, depended on both solvents and the stationary phase of the column used. On a methyl silicone column, the alkane solvents provided wider optimum ranges of initial temperature than aromatic solvents did, for achieving well-shaped symmetrical GC peaks. On a 5% diphenyl: 1% vinyl: 94% dimethyl polysiloxane column, when the aromatic solvents were used, the optimum initial temperature ranges for solutes to form symmetrical peaks were improved to a similar degree as those when the alkanes were used as injection solvents. A mechanism, based on the properties of and possible interactions among the analyte, the injection solvent, and the stationary phase of the capillary column, was proposed to explain these observations. The effect of initial temperature on peak height and peak area of the 16 PAHs and the 10 PCBs was also studied. The optimum initial temperature was found to be dependent on the physical properties of the solvent used and the amount of the solvent injected. Generally, from the boiling point of the solvent to 10 0C above its boiling point was an optimum range of initial temperature at which cthe highest peak height and peak area were obtained.
Author: Bonny Larsson
Publisher:
ISBN:
Category : Aromatic compounds
Languages : en
Pages : 138
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Author: Viktor Grigorʹevich Berezkin
Publisher: Springer
ISBN:
Category : Science
Languages : en
Pages : 216
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Book Description
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.
Author: Justyna Płotka-Wasylka
Publisher: Springer
ISBN: 981139105X
Category : Science
Languages : en
Pages : 449
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Book Description
The book explains the principles and fundamentals of Green Analytical Chemistry (GAC) and highlights the current developments and future potential of the analytical green chemistry-oriented applications of various solutions. The book consists of sixteen chapters, including the history and milestones of GAC; issues related to teaching of green analytical chemistry and greening the university laboratories; evaluation of impact of analytical activities on the environmental and human health, direct techniques of detection, identification and determination of trace constituents; new achievements in the field of extraction of trace analytes from samples characterized by complex composition of the matrix; “green” nature of the derivatization process in analytical chemistry; passive techniques of sampling of analytes; green sorption materials used in analytical procedures; new types of solvents in the field of analytical chemistry. In addition green chromatography and related techniques, fast tests for assessment of the wide spectrum of pollutants in the different types of the medium, remote monitoring of environmental pollutants, qualitative and comparative evaluation, quantitative assessment, and future trends and perspectives are discussed. This book appeals to a wide readership of the academic and industrial researchers. In addition, it can be used in the classroom for undergraduate and graduate Ph.D. students focusing on elaboration of new analytical procedures for organic and inorganic compounds determination in different kinds of samples characterized by complex matrices composition.Jacek Namieśnik was a Professor at the Department of Analytical Chemistry, Gdańsk University of Technology, Poland. Justyna Płotka-Wasylka is a teacher and researcher at the same department.
Author: Jerry Chih-Yuan Han
Publisher:
ISBN:
Category :
Languages : en
Pages : 188
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