Chromatography

•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.



•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 does not move with the sample (stationary phase)

*Stationary Medium*

Principles of Chromatography

1. Analyze
2. Identify
3. Purify
4. Quantify

Principle:

examine a mixture, components, and relations to one another

Analyze

Principle:

determine the identity of a mixture or components based on known components

Identify

Principle:

separate components in order to isolate one of interest for future study

Purify

Principle:

determine the amount of the mixture and components present in the sample

Quantify

TRUE OR FALSE:



•We can use chromatography 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.

TRUE

Formula for Retardation Factor

Rf = __distance moved by substance__

  distance moved by solvent front

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

Give types of Chromatography:

1. Paper
2. Thin-layer
3. Gas
4. Liquid

separates dried liquid samples with a liquid solvent (mobile phase) and a paper strip (stationary phase)

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 attraction to itself is stronger than the force of gravity.

Capillary action

What are the forces that enables the movement of liquid within the spaces of porous material?

Cohesion, adhesion, and surface tension

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

•Separation of components depends on both their solubility in the mobile phase and their differential affinity to the mobile phase and the stationary phase.

¨uses an absorbent material on flat glass or plastic plates.



¨It is used to detect pesticide or insecticide residues in food.



¨Most samples are not colored and need to be visualized with a UV lamp.

Thin Layer Chromatography

¨is also used in forensics to analyze the dye composition of fibers.

Thin Layer Chromatography

What is the mobile phase in Gas chromatography?

a gas mixture composed of an inert carrier gas usually Helium

What is the stationary phase in Gas chromatography?

a packed column into a copper tube

generates an electrical signal which is sent to a recorder

Detector

records the signal

Recorder

True or False:

The temperature of the oven need to be above the boiling points of the components but rather above the “dew point” of the least volatile component

False- it should not need to be above boiling points

Gases from low boiling liquids will spend ____ time dissolved in the liquid phase

less

Gasses from less volatile liquids will spend ____ time in solution with the liquid phase

more

TRUE OR FALSE:

•***The more 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****.*

FALSE- the LESS time a gas spends dissolving, the more time it spends flying

\-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 sample mixture is passed through a column packed with solid particles which may or may not be coated with another liquid. 



¨With the proper solvents, packing conditions, some components in the sample will travel the column more slowly than others resulting in the desired separation.



¨is used in the world to test water samples to look for pollution in lakes and rivers.



¨is used to analyze metal ions and organic compounds in solutions.



¨uses liquids which may incorporate insoluble molecules.

Liquid Chromatography

Types of Liquid Chromatography

1\.  **Liquid/Solid Chromatography** (adsorption chromatography)

 2.  **Liquid/Liquid Chromatography** (partition chromatography)

 3.  **Ion Exchange Chromatography**

 4.  **Gel Permeation Chromatography** (exclusion chromatography)

**Liquid/Solid Chromatography**

adsorption chromatography

**Liquid/Liquid Chromatography**

partition chromatography

**Gel Permeation Chromatography**

exclusion chromatography

The separation mechanism in ____ is based on the competition of the components of the mixture sample for the active sites on an absorbent such as Silica Gel.

**Liquid/Solid Chromatography**

In liquid-liquid Chromatography, what is the stationary phase?

2nd liquid missible to the mobile phase

In liquid-liquid Chromatography, what is the mobile phase?

the solvent

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

is a mechanical sorting of molecules based on the size of the molecules in solution. 



Small molecules are able to permeate more pores and are, therefore, retained longer than large molecules.

Gel-Permeation Chromatography

is a form of column chromatography used frequently in biochemistry and analytical chemistry to separate, identify, and quantify compounds.

High Performance Liquid Chromatography

HPLC utilizes a column that holds _____

1. Chromatographic packing material (stationary phase)
2. a pump that moves the mobile phase through the column
3. detector that shows the retention time of the molecules

¨varies depending on the interactions between the stationary phase, molecules being analyzed, and the solvent(s) used.

Retention time

•uses a polar stationary phase and a non-polar mobile phase, and works effectively for relatively polar analytes

Normal Phase Chromatograaphy

has a non-polar stationary phase and an aqueous, moderately polar mobile phase.

Reversed Phase Chromatography