This document provides an overview of gas chromatography. It discusses the history of chromatography being invented in 1901 by Russian botanist Mikhail Tswett to separate plant pigments. It then explains the basic principles, theory, and instrumentation of gas chromatography. The key components discussed include the carrier gas, columns, injection system, and various detectors. It provides details on how gas chromatography works to separate volatile substances using an inert gas mobile phase and solid or liquid stationary phase.

1. WILL BE PRESENTED BY:
GAS CHROMATOGRAPHY
RAHAT INAYAT ALI – 14CH23

2. Contents Of Topic
 History
 Introduction
 Principle
 Theory
 Instrumentation
Carrier Gas
Flow Regulator
Flow Meter
Columns
Injection System
Detectors
 Advantages and Disadvantages

3. Inventor of Chromatography
Mikhail Tswett (Russian
Botanist), Invented
Chromatography in 1901, During
his research on plant pigments.
He used the technique to separate,
various plant pigments such as:
Chlorophylls
Xanthophylls
Carotenoids.
1872-1919

4. Introduction
 It is an analytical technique, used for separation of
Thermal stable and volatile substances.
Mobile Phase Gas
Stationary Phase Solid or Liquid

5. Principles
 Adsorption
or Depends on the Stationary
 Partition Phase used.
If Stationary phase is:
Liquid -> Gas Liquid Chromatography-> Partition Principle
Solid -> Gas Solid Chromatography-> Adsorption Involved.
In general, compounds with low boiling points (High Vapor
Pressures) spend more time in the Mobile Phase and elute
from the column in a shorter amount of time than
compounds with High Boiling Points.

6. Theory
 The component to be separated from Gas
Chromatography should be:
Volatile
and
Thermo stability.

7. Instrumentation
 Carrier Gas
 Flow Regulator
 Flow Meter
 Injection Device
 Columns
 Temperature Control Device
 Detectors

8. Working Of Gas Chromatography

9.  Carrier Gas
The mobile phase or moving phase is a carrier gas, usually
an inert gas. Such as Helium or an unreactive gas such as
Nitrogen.
Note: Probably more than 90% of the present GC instruments run with
Helium as a carrier gas. Some use Hydrogen and Nitrogen as well.
Hydrogen-> Adv: Better thermal conductivity, Low density.
DisAdv: Reacts with unsaturated compounds, and it is inflammable.
Helium-> Adv: Excellent thermal conductivity.
DisAdv: Expansive.
Nitrogen-> Adv: Inexpensive.
DisAdv: Reduced sensitivity.

10.  Flow Regulator
As carrier gases stored under high pressure, Flow
regulator are used to deliver the Gas with uniform
pressure or flow rate.
 Flow Meter
Rotameter
It is conveniently before the column inlet. It has an
ordinary glass tube like burette with a float held on to the
spring, the level of the float is determined by the flow
rate of the carrier gas and is precalibrated.

11.  Column
Made of Glass or Metal, such as Stainless Steel.
Stainless steel-> Long life, can be handled easily and it reacts with
some compounds.
Glass-> Widely used, as they are inert but highly fragile.
Column can be used both for preparative and analytic purpose
 Types
Packed Column->GSC:Packed with graded adsorbnt or porous polymer.
GLC: Packed with liquid phase coated graded inert solid support.
Open Tubular Column->Made of stainless steel with long capillary tubing in
length and have uniform, narrow internal diameter, know as Capillary of
Golay column.
Support Coated Open Tubular Column-> Improve version of OTC.

12.  Injection System
Injected by Hypodermic Syringe from rubber
septum
A Hypodermic needle is used for rapid delivery of
liquids.

13. Detectors
 Detectors

14.  Advantages:
Relatively inexpensive to acquire and operate.
Low maintenance requirement.
Linearity and detection ranges: FIDS can measure
Organic substances concentration at very low and
very high Levels.
 DisAdvantages:
Can not differentiate b/w different Organic
substances.
They also can not detect Inorganic substances.

15. To ask a Question.. It signals the illiteracy there….
ANY QUESTION ???????
Hmm….?

16. Special Thanks To