F2. CHROMATOGRAPHY Flashcards
- separate and identify the components of a mixture
- allows the molecules present in the mixture to distribute themselves bet. a stationary & mobile medium
- 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
Molecules that spend most of their time in the mobile phase are carried along ____.
CHROMATOGRAPHY
faster
showing a difference, distinctive
Differential
natural attraction or force between things
Affinity
gas or liquid that carries the components
Mobile Medium/ Mobile Phase
the part of the apparatus that does not move with the sample
Stationary Medium/ Stationary Phase
- examine a mixture & its components
- examine their relations to one another
Analyze
- determine the identity of a mixture or a components based on known components.
Identify
- separate components in order to isolate one of interest for further study
Purify
- determine the amount of the mixture
- determine the components present
Quantify
- measure the distance the pigments traveled up and the distance the water traveled
- distance moved by the substance over distance moved by the solvent front
- For substances that are very soluble in the liquid Rf will be close to ____.
- For substances that are rather insoluble in the liquid Rf will be close to ____.
RF - Retardation Factor
- one
- zero
Separates dried liquid samples with a liquid solvent (mobile phase) and a paper strip (stationary phase)
principle of this type of chromatography?
PAPER CHROMATOGRAPHY
- capillary action
- solubility
- 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 attraction to itself is stronger than the force of gravity
Capillary Action
- degree to which a material (solute) dissolves into a solvent
- allows different solutes to be separated by different combinations of solvents
Separation of components depends on both?
Solubility
- solubility in their mobile phase
- differential affinity to the mobile phase & stationary phase
- uses an absorbent material on flat glass or plastic plates.
- used to detect pesticide or insecticide residues in food
- Most samples are not colored and need to be visualized with a UV lamp.
- used in forensics to analyze the dye composition of fibers
THIN LAYER CHROMATOGRAPHY
- used in airports to detect bombs and is used in forensics in many different ways.
- used to analyze fibers on a persons body and also analyze blood found at a crime scene.
used to move a gaseous mixture through a column of absorbent material.
GAS CHROMATOGRAPHY
Helium
one of the most important factors in the solubility of gases in the liquid phases
volatility of the liquid from
which the component vapor drives
will spend less time dissolved in the liquid phase
Gases from low boiling liquids
will spend more time in solution with the liquid phase
Gases from less volatile liquids
The ____ time a gas spends dissolved in the liquid phases, the ____ time it spends flying along with the carrier gas. Thus it moves through the stationary phase ____ quickly.
- less
- more
- more
- used in the world to test water samples to look for pollution in lakes and rivers.
- used to analyze metal ions and organic compounds in solutions.
uses liquids which may incorporate ____ molecules.
LIQUID CHROMATOGRAPHY
insoluble
4 basic liquid chromatography modes:
[named according to the mechanism involved]
- Liquid/Solid Chromatography
- Liquid/Liquid Chromatography
- Ion Exchange Chromatography
- Gel Permeation Chromatography
also known as absorption chromatography
further classified into?
liquid/solid chromatography
- normal phase lsc
- reverse phase lsc
also known as partition chromatography
further classified into?
liquid/liquid chromatography
- normal phase llc
- reverse phase llc
also known as exclusion chromatography
gel permeation chromatography
based on the competition of the components of the mixture sample for the active sites on an absorbent such as Silica Gel.
LSC/ absorption chromatography
- stationary solid surface is coated with a 2nd liquid (the Stationary Phase) which is immiscible in the solvent (Mobile phase).
Partitioning of the sample between 2 phases ________ some components more than others to effect separation.
LLC/ partion chromatography
delays or retains
based on the competition of different ionic compounds of the sample for the active sites on the ion-exchange resin (column-packing).
ION-EXCHANGE CHROMATOGRAPHY
a mechanical sorting of molecules based on the size of the molecules in solution
- able to permeate more pores
- retained longer than large molecules
GEL-PERMEATION CHROMATOGRAPHY/ exclusion chromatography
Small molecules
HIGH PERFORMANCE LIQUID CHROMATOGRAPHY is also known as?
HPLC - high pressure liquid chromatography
- form of column chromatography
- used frequently in biochemistry and analytical chemistry to separate, identify, and quantify compounds
it utilizes a (3)?
HPLC
- column
- pump
- detector
- holds chromatographic packing material (stationary phase);
- moves the mobile phase(s) through the column; and
- shows the retention times of the molecules
- column
- pump
- detector
depends on the interactions bet. the stationary phase, molecules being analyzed, and the solvent(s) used.
retention time
- polar stationary phase
- non-polar mobile phase
- works effectively for relatively polar analytes
Normal Phase Chromatography
- non-polar stationary phase
- aqeous, moderately polar mobile phase
Reversed Phase Chromatography