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Gas Chromatography

The document discusses gas chromatography, including its definition, types, principle, technique, and components. Gas chromatography is a technique used to separate gases, volatile liquids, or volatile solids using an inert gas carrier and columns containing an adsorbent or partitioning material to separate components at different rates as they emerge from the column and pass through detectors.

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28 views2 pages

Gas Chromatography

The document discusses gas chromatography, including its definition, types, principle, technique, and components. Gas chromatography is a technique used to separate gases, volatile liquids, or volatile solids using an inert gas carrier and columns containing an adsorbent or partitioning material to separate components at different rates as they emerge from the column and pass through detectors.

Uploaded by

Mooma fatima
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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Gas chromatography

Introduction

Definition

Technique of chromatography in which mobile phase is gas is known as gas chromatography.

Or

Technique of chromatography which is used for the separation of gases and volatile liquids or
volatile solids in gaseous state is known as gas chromatography.

Types

Gas /solid chromatography

Gas /liquid chromatography

Principle

Adsorption (Gas /solid chromatography)

Partition (Gas /liquid chromatography)

Technique

Small sample is injected into stream of an inert gas i.e.nitrogen,hydrogen,CO 2 ,argon, helium,
which carries it into a column containing a suitable medium capable to retard the flow of of
individual components as they flow through the column by varying degrees. The separated
component s emerges from column at discrete intervals and passes through detectors.

Difference in adsorption or partition on the material in column is the factor which makes
separation possible.

Components of gas chromatography

1-Carrier gas

Sample is injected into stream of an inert gas i.e.nitrogen,hydrogen,CO 2 ,argon, helium, which
carries it into a column.

 Inert
 Available at low cost
 Produce definite response on detector
 Should be pour
 Choice of gas depends on type of dectectors,helium and hydrogen with katherometers
 Nitrogen is used with flame ionization detectors.

2-Flow control valve

Control flow of gas through column. Accurate flow of carrier gas is important for high column
efficiency and qualitative and quantitative analysis.

Types of flow meter valve

Float flow meter

When no gas is flowing through the meter the small float remain at the bottom of tapering
vertical glass tube when in use the float is moves in tube until it own weight balances thrust of
gas flowing through meter. The vertical weight of float therefore continuously denotes the flow
rate.

Capillary flow meter

The capillary flow measure.es the pressure developed in forcing the gas to pass through a length
of capillary tubing this directly proportional to the flow rate

Soap bubble flow meter

Soap bubble are generated by gentle pressing the bulb at the bottom .The time taken by the
bubble to move along a given length of tube provides a measurement of flow rate.

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