2. The word ‘Chromatography’ is derived from the two Greek
words- Chroma means colour and graphein means writing
Chromatography is a technique for separating mixtures into their
components through two phases; one stationary (stationary phase)
and the other moving in definite direction (mobile phase)
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3. Invention of Chromatography
Micheal Tswett invented the
chromatography in 1901 during
his research on plant pigments.
He used the separation technique
to separate various plant pigments
such as chlorophyll, xanthophyll,
carotenoids etc.
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4. Chromatography principle
Chromatography is based on
the principle of the partition
of the solute between two
phases. Chromatography
usually consists of a mobile
phase and a stationary phase.
• The mobile phase usually
refers to the mixture of
the substances to be
separated dissolved on a
liquid or a gas.
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5. ................. Principle continued
• The stationary phase is a porous solid matrix through which the
sample contained in the mobile phase percolates.
• The interaction between the mobile and stationary phase results
in the separation of the mixture of the compounds.
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7. Gas Chromatography
Gas chromatography is an
analytical technique in which
the sample mixture is injected,
vaporized into a stream of
carrier gas (as nitrogen or
helium) moving through a
column containing a stationary
phase, separated into its
component according to their
affinity to the stationary phase
and detected.
Nobel prize winner John Porter
Martin is the father of modern
gas chromatography
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9. Injector
o The injector is heated so
that all components in the
sample is vaporized
o The temperature of the
sample port is usually
about 50º C higher than the
boiling point of the least
volatile component of the
sample.
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10. Column
o This is where the chromatographic separation of the sample
occurs.
o It is the heart of the system
o The column is coated with a
stationary phase which greatly
influences the separation of the
compounds
o Conventional column is of 1/8 –
¼ OD, 6-8 feet in length, made
of stainless steel or glass tube
o Capillary column is of 0.1-0.5
ID, 10-100 meters in length
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11. Carrier gas
o An inert gas like helium,
hydrogen or nitrogen which is
used to sweep a mixture to be
separated through a gas
chromatograph
o The sample is pushed through
the gas chromatographic
column
o The gas chromatographic
column is cleaned out after
sample analysis
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12. Detectors
o It is the part of the gas
chromatograph which signals the
change in composition of the
mixture passing through it.
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15. Applications of Chromatography
o Detection of steroids
o Analysis of food
o Separation and identification of lipid, protein, carbohydrates,
vitamins etc.
o Analysis of dairy products
o Separation and identification of volatile materials like plastics,
natural and synthetic polymers
• References: McMurry, John (2011) Organic chemistry: with biological
applications (2nd ed.).
Handbook of Thin-Layer Chromatography. Marcel Dekker
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