CHEM: CHROMATOGRAPHY Flashcards
Is a technique used to separate and identify the
components of a mixture.
• Works by allowing the molecules present in the mixture to distribute themselves between a
stationary and a mobile medium.
CHROMATOGRAPHY
Molecules that spend most of their time in the
mobile phase are carried along faster.
CHROMATOGRAPHY
is a laboratory technique that separates components within a mixture by using the differential affinities of the components for a
mobile medium and for a stationary adsorbing
medium through which they pass.
Chromatography
showing a difference, distinctive
Differential
natural attraction or force between things
Affinity
gas or liquid that carries the components (mobile phase)
Mobile Medium
the part of the apparatus that allows does not move with the sample (stationary phase)
Stationary Medium
use to separate the components of inks and dyes, such as those found,in pens, markers, clothing, and even candy shells. Chromatography can also be used to separate the colored pigments in plants.
chromatography
can be determined by measuring the distance the pigments traveled up the strip and the distance the water traveled. You will need to calculate the RF for each of the colors that are present in a sample.
RF (RETARDATION FACTOR)
For substances that are very soluble in the liquid Rf will be
close to 1
For substances that are rather insoluble in the liquid Rf will be
close to 0
• Separates dried liquid samples with a liquid solvent (mobile phase) and a paper strip (stationary phase)
PAPER CHROMATOGRAPHY
PRINCIPLES OF PAPER CHROMATOGRAPHY
– the movement of liquid within the
spaces of a porous material due to the forces of
adhesion, cohesion, and surface tension. The liquid is able to move up the filter paper because its
Capillary Action
PRINCIPLES OF PAPER CHROMATOGRAPHY
the degree to which a material (solute)
dissolves into a solvent. Solutes dissolve into
solvents that have similar properties. (Like
dissolves like) This allows different solutes to be
separated by different combinations of solvents.
Solubility
PRINCIPLES OF PAPER CHROMATOGRAPHY
depends on both their solubility in the mobile phase and their differential affinity to the mobile phase and the stationary phase.
Separation of components
• uses an absorbent material on flat glass or plastic plates.
• It is used to detect pesticide or insecticide residues in food.
THIN LAYER CHROMATOGRAPHY
is also used in forensics to analyze the dye composition of fibers.
• Most samples are not colored and need to be
visualized with a UV lamp.
Thin-layer chromatography
• is used in airports to detect bombs and is used in forensics in many different ways.
• It is used to analyze fibers on a persons body and also analyze blood found at a crime scene.
GAS CHROMATOGRAPHY
is used to move a gaseous mixture through
a column of absorbent material.
Helium
A gas mixture, called the Mobile Phase, composed of an inert “carrier” gas (usually Helium) and various other chemical components in the vapor phase introduced at the Injection Port pass through a non-
moving material,
gas mixture
usually tightly packed into a copper tube called the Column…
- which separates the gas stream into its
particular components based on how “quickly”
they move through the stationary phase.
Stationary Phase
generates an electrical signal which is sent to a…
Detector
record the signal.
Recorder
(t or f)
• The less time a gas spends dissolved in the liquid phases, the more time it spends flying along with the carrier gas. Thus it moves through the stationary phase more quickly.
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