Gass chromatography pptx all information about Gass chromatography

1. Gas Chromatography
Physical and Analytical chemistry

2. Columns in Gas Chromatography:
Shapes of Column:
• W-shaped (less used)
• U-shaped
• Coiled shaped (most used)

3. Materials of Column:
• Anything which is inert can be used as a column. On the other hand,
anything which is reactive cannot be used as a column. Usually column in
gas chromatography is made up of:
• Copper
• Aluminium
• Stainless steel (a mixture of metals)
• Glass

4. Types of Columns:
• There are two general types of columns:
Packed column Capillary column
1. The diameter of packed column is The diameter of capillary column is
greater. ( 2-10 mm) smaller. ( 0.2-0.5 mm)
2. The length of packed column is The length of capillary column is
smaller. ( 1-4 m) greater (20-80 m)
3. Sample holding capacity is greater. Sample holding capacity is smaller.

5. Diagram of Packed Column:

6. Formation of Packed Column:
• The following steps are involved in formation of packed column:
1. The stationary phase and supporting material is mixed with each other and
filled inside the column.
2. The column is coiled and then heat it.
3. Now packed column is prepared for gas chromatography.

7. Advantages of Packed column:
1. Higher sample capacity
2. Better resolution for certain compounds
3. Ability to handle a wide range of sample types
4. Cost-effective compared to capillary columns

8. Disadvantages of Packed Column:
1. Lower separation efficiency
2. Limited peak capacity
3. Higher susceptibility to column bleed
4. Less suitable for analyzing volatile and heat-sensitive compounds

9. Capillary column:
• Small amount of sample is required.
• The temperature of column should be 150-300 degree Celsius.
• It is more efficient as compared to packed column.

10. Types of Capillary Column:
There are generally three types of capillary column:
1. Wall coated open tabular column ( WCOT column)
2. Support coated open tabular column ( SCOT column)
3. Porous layer open tabular column ( PLOT column)
• WCOT and SCOT columns are used in gas-liquid chromatography(GLC),
while PLOT column is used in gas-solid chromatography(GSC).

11. Wall coated open tabular column(WCOT):
• The stationary phase in WCOT column is liquid.
• The stationary phase is passed through the column and a thin layer of
stationary phase is coated with its walls and a narrow bore is left behind.

12. Support coated open tabular column ( SCOT):
• The stationary phase in SCOT column is liquid.
• Stationary phase is mixed with supporting material and a thin layer of
supporting media is coated with stationary phase placed inside the column.

13. Porous layer open tabular column ( PLOT):
• Stationary phase in PLOT column is solid.
• The stationary phase is mixed with supporting media and placed with a thin
layer inside the column.

14. Diagrams of WCOT, SCOT and PLOT
columns:

15. Types of Phases in Gas Chromatography:
Stationary Phase
• It is immovable .
• It should be non-volatile.
• It should be thermally stable.
• The boiling point should be at least
100 degree Celsius.
Mobile phase
• It is movable.
• It should be volatile.
• It should be inert towards sample
constituents and the stationary
phase.

16. Applications of Gas Chromatography:
1. Food analysis:
The food industry relies on the technique of gas
chromatography for several applications, including the quantitative and
qualitative analysis of food, the analysis of food additives, components of
flavor and aroma, and the detection and analysis of contaminants such as
environmental pollutants, pesticides, fumigants, and naturally occurring toxins.
Gas chromatography remains a highly favored method due
to its ease of use and cost-effectiveness.

17. Applications of Gas Chromatography:
2. Quality control:
Manufacturing relies on gas chromatography for quality
control, companies that produce cars, chemicals, and pharmaceuticals, in
particular, are big adopters of the technology.
The pharmaceutical industry uses gas chromatography to
help produce pure products in large quantities. The method is used to ensure
the purity of the produced material, eliminated inconsistencies in
pharmaceutical products. The industry also uses gas chromatography to analyze
compounds to check for trace contaminants.

18. Applications of Gas Chromatography:
3. Research:
Gas chromatography is fundamental to many research areas, in
particular, for the analysis of meteorites and natural products. Scientists use gas
chromatography to analyze the composition of meteorites that fall to the earth.
This provides vitally important information regarding the nature
of life outside of earth, as well as revealing details about primitive life on earth.

19. Applications of Gas Chromatography:
4. Forensics:
For many years gas chromatography has been used in forensic
science. Mostly, it is used to determine the circumstances of a person’s death,
such as whether they ingested poison, or consumed drugs or alcohol in the
hours prior. Scientists take samples of blood and fibers from the crime scene
and analyze them using gas chromatography to help investigators piece
together the facts.

20. Applications of Gas Chromatography:
5. Measuring air pollution:
Air pollution has become an increasing problem in
recent decades. Rapid urbanization has lead to more people living in cities
where they are exposed to the pollutants expelled by vehicles and industry.
Also, there is a growing body of evidence that has implicated air pollution as a
risk factor in developing numerous diseases, such as cancer.

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