1. STK1094 Analytical Chemistry I
Dayang Norafizan binti Awang Che
Faculty of Resource Science and Technology
Universiti Malaysia Sarawak
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2. LU 8: Analytical Separation
Techniques
Learning Objectives
At the end of this lesson, students should be
able to:
• Define the chromatography term
• Explain different types of chromatography
• Explain the principles of chromatography
3. What is Chromatography?
• Chromatography is a technique for
separating mixtures into their components
in order to analyze, identify, purify, and/or
quantify the mixture or components.
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Separate
• Analyze
• Identify
• Purify
• Quantify
ComponentsMixture
CHROMATOGRAPHIC SEPARATIONS
4. Uses of Chromatography
• Chromatography is used by scientists to:
• Analyze – examine a mixture, its components,
and their relations to one another
• Identify – determine the identity of a mixture
or components based on known components
• Purify – separate components in order to
isolate one of interest for further study
• Quantify – determine the amount of a
mixture and/or the components present in
the sample
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5. Types of Chromatography
• Liquid Chromatography
separates liquid samples with a liquid solvent (mobile phase) and a
column composed of solid beads (stationary phase).
• Gas Chromatography
separates vaporized samples with a carrier gas (mobile phase) and a
column composed of a liquid or of solid beads (stationary phase).
• Paper Chromatography
separates dried liquid samples with a liquid solvent (mobile phase)
and a paper strip (stationary phase).
• Thin-Layer Chromatography
separates dried liquid samples with a liquid solvent (mobile phase)
and a glass plate covered with a thin layer of alumina or silica gel
(stationary phase).
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6. *Terms in Separation Techniques*
• Stationary phase: a phase that is fixed in place
either in a column or on a planar surface.
• Mobile phase :a phase that moves over or
through the stationary phase, carrying the
analyte with it.
• Eluent: a solvent used to carry the
components of a mixture through stationary
phase.
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7.
8. Chromatography
• Greek word chroma – “color” and graphein
– “to write”.
• Separations method - differences in
partitioning behavior (migration rates)
between a flowing mobile phase and a
stationary phase to separate the
components in a mixture.
• Column holds the stationary phase and the
mobile phase carries the sample through it.
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9. Chromatography Basics
How it works:
sample is loaded onto the polar stationary phase.
Polar compounds will adsorb onto the stationary
phase to a greater extent than non-polar
compounds.
The mobile phase (eluting phase) helps “push” or
elute the compounds either down a column (for
CC) or up a plate (for TLC).
The main concept to consider in chromatography is polarity.
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10. Polarity & Intermolecular Attractive
Forces
• More polar compounds will be more attracted to silica gel than non-polar
compounds due to intermolecular attractive forces
- a dipole-dipole interaction.
• The more non-polar compounds will travel more easily and more quickly
through the stationary phase.
• The mobile phase helps carry the compounds through the stationary
phase.
•Separation of compounds in a mixture is possible because compounds
have different polarities. Non-polar compounds will elute first and polar
compounds will elute last.
Si
OH
O
O
O
Si
+
-
-
-
+
Silica gel, [SiO2]n
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11. Components that are weakly retained by stationary
phase will move through the system more rapidly
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