Gas chromatography (GC) is a method of separation which employs a gas mobile phase and either a solid (GSC) or a liquid (GLC) adsorbed on a solid as a stationary phase. Gas chromatography is capable of separating very complex mixtures and the selectivity can be adjusted to separate almost any given pair of solutes by judicious choice of the stationary phase. The major limitation of gas chromatography is the requirement that the solute have a reasonable vapor pressure at a temperature where it is still stable.

Free Books and Brochures

Principles and Practice of Chromatography
Library4Science Book Size 2023 K
Chromatography The Principles and Practice of Chromatography describes the fundamental physical-chemical processes involved in a chromatographic separation together with the basic equipment necessary.

SpectraSYSTEM HPLC
Thermo Fisher Scientific Brochure Size 2665 K
Analytical Systems The Thermo Fisher Scientific family of SpectraSYSTEM instruments are completely ROHS compliant providing HPLC analysis in a compact, modular design for every type of laboratory.

Environmental Solutions with HPLC and Related Technologies
Agilent Technologies Europe Brochure Size 2519 K
HPLC This guide gives a condensed overview of the application solutions for this market, with particular emphasis on LC, LC/MS, and selected LC-ICP-MS applications. Liquid phase and SPE sample preparation techniques used prior to some GC or GC/MS analyses

QUATERNARY HPLC SYSTEMS
Cecil Instruments Brochure Size 844 K
Analytical Systems Cecil Instruments offers both high pressure and low pressure gradient forming complete HPLC systems.

Name
Email Address
Company/Org.
Your Job:


Country:


Remember me Free newsletter

Library4science 1 click document service.

Close Old Password Required
New Password
Name
Email Address
Company/Org.
Your Job:


Country:


Require password for requests:
Remember me Free newsletter

Author: RPW Scott Book:Gas Chromatography
Section:YES   Introduction

, in one of its several forms, is the most commonly used procedure in contemporary chemical analysis and the first configuration of chromatography equipment to be produced in a single composite unit and made commercially available was the gas chromatograph. Gas chromatography was invented by A. J. P. Martin who, with R. L. M. Synge, suggested its possibility in a paper on liquid chromatography published in 1941 (1). Martin and Synge recommended that the liquid mobile phase used in liquid chromatography could be replaced by a suitable gas. The basis for this recommendation was that, due to much higher diffusivities of solutes in gases compared with liquids, the equilibrium processes involved in a chromatographic process (see Principles and Practice of Chromatography) would be much faster and thus, the columns much more efficient and separation times much shorter. So the concept of gas chromatography was envisioned more than fifty years ago, but unfortunately, little

YES   Introduction

Author: RPW Scott Book:Principles and Practice of Chromatography
Section:Principles   Introduction

, the primary classification of chromatography is based on the physical nature of the mobile phase. The mobile phase can be a gas or a liquid which gives rise to the two basic forms of chromatography, namely, gas chromatography (GC) and liquid chromatography (LC). The stationary phase can also take two forms, solid and liquid, which provides two subgroups of GC and LC, namely; gas–solid chromatography (GSC) and gas–liquid chromatography (GLC), together with liquid solid chromatography (LSC) and liquid chromatography (LLC). The different forms of chromatography are summarized in Table 1. Most thin layer chromatography techniques are considered liquid-solid systems although the solute normally interacts with a liquid-like surface coating on the adsorbent or support or, in some cases an actual liquid coating. Table 1 The Classification of Chromatography chromatography systems

Principles   Introduction

Author: RPW Scott Book:Gas Chromatography
Section:YES   Preparative-Gas-Chromatography

Preparative Gas Chromatography Gas chromatography has not been used extensively for preparative work although its counterpart, liquid chromatography, has been broadly used in the pharmaceutical industry for the isolation and purification of physiologically active substances. There are a number of unique problems associated with preparative gas chromatography. Firstly, it is difficult to recycle the mobile phase and thus large volume of gas are necessary. Secondly, the sample must be fully vaporized onto the column to ensure radial distribution of the sample across the column. Thirdly, the materials of interest are eluted largely in a very dilute form from the column and therefore must be extracted or condensed from the gas stream which is also difficult to achieve efficiently. Finally, the efficient packing of large GC columns

YES   Preparative-Gas-Chromatography

Author: RPW Scott Book:Gas Chromatography Detectors
Section:GC-Detectors   References

Publications,       (1957)131.  9.   H. Boer, "Vapor Phase Chromatography" (Ed. D.H. Desty and C.        L. A. Harbourn), Butterworths Scientific Publications (1957)169. 10. D. W. Grant, "Gas Chromatography 1958" (Ed. D. H. Desty),       Butterworths Scientific Publications, (1957)153. 11. N. H. Ray, J. Appl. Chem., 4(1954)21. 12. 1.  J. Harley, W. Neland V. Pretorious, Nature, London,       181(1958)177. 13.  I. G. McWilliams and R. A. Dewer, "Gas Chromatography 1958",        (Ed. D. H.Desty), Butterworths Scientific Publications 14.  S. A. Beres, C. D. Halfmann, E. D. Katz and R. P. W. Scott,       Analyst, 112(1987)91. 15.L. Ongkiehong, "Gas Chromatography 1960" (Ed. R. P. W. Scott)        Butterworths, London (1958)9. 16. D. H. Desty, A. Goldup and C. J. Geach, "Gas Chromatography         1960"  (Ed. R. P. W. Scott)  Butterworths, London (1958)156. 17.  H, F. Calcote and I. R. King, "The

GC-Detectors   References

Author: RPW Scott Book:Gas Chromatography - Tandem Techniques
Section:GC-Tandem   GC-IR

(ca 100 nsec) so that all the ions in the source are accelerated virtually simultaneously. The ions then pass through the third electrode into the drift zone and are eventually collected by the sensor electrode. The time of flight mass spectrometer is not employed extensively in gas chromatography/mass spectroscopy combination systems as it is more commonly used to examine high molecular weight materials Many analysts that use GC/Mass Spectrometer combined systems are neither specialists in gas chromatography or mass spectrometry and may need the support of experienced gas chromatographers or mass spectroscopists for particularly challenging samples. For those who wish to study mass spectrometry further, an excellent discussion on general organic mass spectrometry is given in Practical Organic Mass Spectrometry edited by Chapman (9).   Gas Chromatography IR Spectroscopy (GC/IR) Systems   IR spectra were initially obtained off-line, by condensing the eluted solute in a

GC-Tandem   GC-IR

Author: RPW Scott Book:Principles and Practice of Chromatography
Section:Principles   Introduction

along time and it was not until the late 1930s and early 1940s that Martin and Synge(2) introduced liquid-liquid chromatography by supporting the stationary phase, in this case water, on silica in a packed bed and used it to separate some acetyl amino acids. In their paper, they recommended replacing the liquid mobile phase by a suitable gas, as the transfer of sample between the two phases would be faster, and thus provide more efficient separations. In this manner, the concept of gas chromatography was created but again, little notice was taken of the suggestion and it was left to Martin himself and A. T. James to bring the concept to practical reality nearly a decade later. In the same publication in 1941, the essential requirements for HPLC (High Performance Liquid Chromatography) were unambiguously defined

Principles   Introduction


Free Books
Free Brochures