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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.”

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