# What are last and most fundamental factors which can help in the effective and best separation in the methodology of chromatography?

What are last and most fundamental factors which can help in the effective and best separation in the methodology of chromatography?

There are following three basic concepts which can help in the separative methodology of process of chromatography

Peak shape

Selectivity

Efficiency

If coefficient of distribution does not depend upon the concentration than a graph can be plotted between

Amount of different particles present along the stationary phase

Concentration of different components which exists within the mobile phase

What kind of name should be given to the graph plotted in the basis if above discussion is taken under observation?

The type of graph is known as isotherm.

Symbols of nonlinear shaped graph

Non linear shaped graph are common,and specially have convex type shape.

General discussed type of graph in all kinds of chromatography

Commonly linear “convex type” of graph are used in experimental which may be possible in the procedure of chromatography.

Which type of graph are used in partition chromatography?

“Concave isotherms” graph are used in partition chromatography.

How concave shaped graph can be produced?

When a large amount of the sample is packed within the chromatographic column than following changes takes place

Retention time of the solute will be increased

At the end concave shaped isotherm graph is produced

How convex shaped isotherm graphs are produced?

If sample is used in small amount than column also have small amount of sample.As a result of this procedure Concave shaped graph formation can take place.

Selectivity

Definition

Selectivity can be defined as following

“The factor which describes degree of measure of the stationary phase shows for one solute over another”.

Units of selectivity

Selectivity is a ratio so it has no units.

Formula of selectivity

An ideal relationship for the factor of selectivity is given as following

a=k1/K2

Description of formula:

k1= Distribution co efficient s for solute of kind one

K2= Distribution co efficient s for solute of kind two

Efficiency

Definition

“Efficiency in chromatography is a quantitative factor which can be described by that how many numbers of theoretical plates are present.”

How number of theoretical plates are represented?

Representation of number of theoretical plates is done by n alphabetical word N or height which is equivalent to the theoretical plate H or (HETP).

Relationship between H and N

H=L/N

L= length of the column.

Definition of theoretical plate

“Length of the column in which the amount of solute which under goes in one complete equilibrium.”