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What do you know about analytical separations?

What do you know about analytical separations?

Analytical separations are widely distributed over all fields of chemistry now applied method of analyzing a compound have some deficiencies .But here we discuss the most widely used technique Chromatography.

First we will discuss history of chromatography:

In Ancient times Chromatography was used for the separation of colour compounds  such as plant pigments Different coloured inks.As plant contain different types of chlorophyll's they are separated in a best way by the use of chromatography.

Discovery of chromatography:

Initially chromatography was used for the separation of coloured compounds and herbal components.  So chromatography was discovered by M.S in 1903 .he used plant pigments for the separation originally M.S was a Russian botanist.

Importance of Chromatography :

Chromatography is such a unique which has won two noble prize.More than 60% separations are done by the use of this technique.Mostly organic or inorganic compounds are also separated.Homogeneous mixtures  are also well separated by applying this technique.It is also used for the identification of compound either compound is solid or liquid.

Types of chromatography


Chromatography can be classified in to for main types :
Liquid chromatography
Gas chromatography
Thin layer chromatography
Paper chromatography

Chromatography can be further classified in to following main types:

ion -exchange chromatography
Gel chromatography
High -performance liquid chromatography
Before discussion of these powerful tools of an analyst or a scientist we have should have a short look on  

Important terms of chromatography:

Chromatography is although a dramatic technique and works on following principle which mainly consists of following two phases:
1)Mobile phase(Moving Phase )
This phase always move over the stationary phases and often a solvent.

2)Stationary phase(Non-moving phase)

This phase is found in a solute form and works with mobile phase.                               
All of these use full & modern branches of chromatography are briefly discussed below:
Detailed & brief explanation of-some high lighted branches have following technical use & are of great importance in all fields of chemistry especially in analytical chemistry:

In this type of chromatography mobile phase is always a solvent .

 General Mechanism of Liquid -Liquid chromatography:

Solute distributes it self among two phases by depending on their partition coefficients.

Types of Liquid chromatography:

there are following types of liquid chromatography:
liquid-liquid chromatography
Liquid solid chromatography

Liquid  liquid chromatography comprises two sub phases based on their types:

Normal phase chromatography
Reverse phase chromatography
Both phases are discussed according to the polarities of mobile phase and stationary phase

Normal phase chromatography:

In this type stationary phase is always  polar and mobile phase is always a non-polar.
So in this case if silica is used on the place of stationary phase than this phase is also called as normal phase chromatography.

Reverse phase chromatography:

in this type of chromatography mobile phase is always a polar component and stationary phase is always a non-polar.

Liquid-solid chromatography:

Liquid -solid chromatography is mainly done in a column.Liquid solid column chromatography is most widely applicable and use full technique. 

General mechanism of liquid column chromatography is given as follows:

Components are being separated wihin the mobile phase along the stationary phase .If sample components are coloured than they can be seen in the forms of bands otherwise another technique HPLC is used for further process.
Another interesting information is that first phenomena of chromatography was observed in the form of  liquid solid (column chromatography) chromatography.


Gas chromatography:

Discovery of gas chromatography

Gas chromatography was discovered by  JAMES & MARTIN in 1952 .

Defination 

Gas chromatography can be defined as follows
 Gas chromatography is such a technique in which separation is done on the process of partition  between two imiscible  phases:

Gaseous mobile phase (carrier gas) Stationary solid (immobilised liquid phase) 

Carrier gas is kept in a cylinder with pressure or in a gas generating cylinder.Types of a carrier gas mainly effects on efficiency of a column.

Primary components of  gas chromatography 

Primary components of  gas chromatography scheme are given as follows:
Carrier gas system
Sample injection method
Detectors
Column
Integrator
Applications of gas chromatography:
Gas chromatography is widely accepted application in the field of analytical chemistry:

Complex mixtures :

Complex mixtures can be separated by the application of this technique.

 Micro technique:

This is considered as a micro technique even a little quantity of sample can be tested with the help of gas chromatography.


Multifaceted and rapid :


As compared to other chromatographic technique gas chromatography is multifaceted and rapid action technique. Gas chromatography is also used for the separation of vitamins also.

Thin-layer chromatography:

Discovery of thin layer chromatography:
Thin layer chromatography was discovered by lazmailov and Shraiber in era of 1938 by the use of plant extract.They used an adsorbent layer on a microscopic slide by the process of spotting the slides  and further passed them from drying process.

Principle of  Thin layer Chromatography:

Thin layer chromatography works in the process of adsorption.In this technique two phases are used on the base of different solubility. Components which have stronger interaction with the stationary phase moves at a slower speed.
The components having less affinity with the stationary phase move at a faster rate.

Applications of Thin layer chromatography:

Thin layer chromatography is used for the identification of substances.

purity checking:

This dramatic technique is also used for the test that either a compound is pure or not.

Quick technique:

This method of chromatography is also a quick & fast method.

Amount of material:

 The required amount of material in this technique is very small amount .placement of separated components:
Separated compounds are seen on the stationary phase in this process.

Paper chromatography:

Discovery of paper chromatography:

Paper chromatography was discovered by two British biochemists Archer John Porter Martin (1910) and Richard Laurence Millington Synge (1914). In era of 1941 Martin and Synge Start working together on proteins, which are made up of many amino acids. 
In paper chromatography cellulose is use as a support as a stationary phase.
Mobile phase consists of a soluble solvent or fluid.

Applications of paper chromatography:

Paper chromatography has following interesting applications:

For DNA & RNA:

It is used for the sequencing of DNA & RNA .

Main tool of analytical chemistry:

Paper chromatography is used on a larger scale for qualitative tool in analytical chemistry .

In drugs :

Paper chromatography is also used for the separation of impurities in drugs.

Use in different fields:



This interesting branch of  chromatography can also be applied in the field of both organic and in-organic compounds.

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