Page 164 - Academic Press Encyclopedia of Physical Science and Technology 3rd Analytical Chemistry

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Encyclopedia of Physical Science and Technology EN006F-275 June 29, 2001 21:12

Gas Chromatography

Milos Novotny
Indiana University

I. Gas Chromatographic Molecular Separation
II. Physical Principles
III. Separation Columns
IV. Detectors and Ancillary Techniques
V. Instrumentation
VI. Applications

GLOSSARY components to the stationary phase (a solid or a liquid),
while the mobile phase (a gas) migrates them through
Mobile phase Gas containing the compounds to be sep- the system. GC is a dynamic separation method, where
arated while migrating through the stationary phase. the separation of components occurs in a heterogeneous
Stationary phase Solid or liquid whose physical prop- phase system.
erties affect the separation of the mobile-phase com-
pound.
I. GAS CHROMATOGRAPHIC
MOLECULAR SEPARATION
GAS CHROMATOGRAPHY (GC) is a physical separa-
tion method used extensively in scientific investigations, Separating chemical substances from each other has been
chemical practice, petroleum technology, environmental extremely important to various branches of science and
pollution control, and modern biology and medicine. Its technology for many years. Simple separation procedures
primary role is to separate various chemical compounds such as distillation, crystallization, precipitation, and sol-
that were introduced into the system as a mixture and to vent extraction have been used by humankind from time
determine quantitatively their relative proportions. When immemorial. More refined forms of separation, such as
combined with other physicochemical methods, GC can chromatography and electrophoresis, have been among
also provide qualitative (structural) information on the the major causes of scientific revolution during the last
separated substances. The method is limited to relatively several decades of this century.
volatile (low-molecular-weight) compounds. The princi- Gas chromatography is one of the several chro-
ple of separation is a relative affinity of various mixture matographic methods. The scientific principles of

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