Lecture 7 8 Liquid Chromatography
Separation techniques
LIQUID CHROMATOGRAPHY
‘THE ART OF SEPARATION’
CHROMATOGRAPHY – AN INTRODUCTION
Chromatography is a technique through which a mixture of chemical components are separated, identified and determined accurately. This technique while provides a way for analytical separations, also useful for preparative techniques by which pure compounds can be obtained.
Detector Signal
Blue Compound
Sample Injection + Mobile Phase
Retention Time
Red Compound
It is i defined d fi d as a technique t h i b which by hi h the th components t off a mixture i t are separated t d based b d upon the rates at which they are moved or carried over a stationary phase by a gaseous or liquid mobile phase” Based on the mobile phase this technique can be classified as:
‘Liquid
Liquid Chromatography
Chromatography’ and ‘Gas
Gas Chromatography
Chromatography’.
With the basic two classifications as LC and GC, there are further classifications based on the type of stationary phase (column), mobile phase (eluent) and type of separation occurs within the column. column The simplified version on various types is given as follow:
Chromatography
Liquid Chromatography
HPLC
Adsorption
Partition
Ion Exchange
TLC/PC
Adsorption
SEC
GPC
GFC
Gas Chromatography
GSC
Adsorption
GLC
Partition
Apart from normal liquids as the mobile phases, supercritical fluids such as liquid CO2 can also be used as mobile phase and the technique is designated as Supercritical Fluid
Chromatography (SFC).
CHROMATOGRAPHY – HPLC PRINCIPLES AND MODES
Introduction:
As seen, in liquid chromatography the mobile phase used is a liquid solvent. In earlier days this was carried out in long packed glass columns with wide diameter. But the flow rates of the mobile phase was very slow and the separation times were sometimes took several hours.
Nowadays, the speed of the flow rates has been improved by applying high pressure to the gp pumps p of various types yp and the p performance is improved, p , this
LIQUID CHROMATOGRAPHY
‘THE ART OF SEPARATION’
CHROMATOGRAPHY – AN INTRODUCTION
Chromatography is a technique through which a mixture of chemical components are separated, identified and determined accurately. This technique while provides a way for analytical separations, also useful for preparative techniques by which pure compounds can be obtained.
Detector Signal
Blue Compound
Sample Injection + Mobile Phase
Retention Time
Red Compound
It is i defined d fi d as a technique t h i b which by hi h the th components t off a mixture i t are separated t d based b d upon the rates at which they are moved or carried over a stationary phase by a gaseous or liquid mobile phase” Based on the mobile phase this technique can be classified as:
‘Liquid
Liquid Chromatography
Chromatography’ and ‘Gas
Gas Chromatography
Chromatography’.
With the basic two classifications as LC and GC, there are further classifications based on the type of stationary phase (column), mobile phase (eluent) and type of separation occurs within the column. column The simplified version on various types is given as follow:
Chromatography
Liquid Chromatography
HPLC
Adsorption
Partition
Ion Exchange
TLC/PC
Adsorption
SEC
GPC
GFC
Gas Chromatography
GSC
Adsorption
GLC
Partition
Apart from normal liquids as the mobile phases, supercritical fluids such as liquid CO2 can also be used as mobile phase and the technique is designated as Supercritical Fluid
Chromatography (SFC).
CHROMATOGRAPHY – HPLC PRINCIPLES AND MODES
Introduction:
As seen, in liquid chromatography the mobile phase used is a liquid solvent. In earlier days this was carried out in long packed glass columns with wide diameter. But the flow rates of the mobile phase was very slow and the separation times were sometimes took several hours.
Nowadays, the speed of the flow rates has been improved by applying high pressure to the gp pumps p of various types yp and the p performance is improved, p , this
References: 1. ‘Gas and Liquid Chromatography in Analytical Chemistry’, R M Smith, John Wiley & Sons, 1988. 2. ‘Chromatographic Methods’, A. Braithwaite and F. J. Smith, 5th Edition, Blackie Academic & Professional, Glasgow, 1996. 3. ‘Principles of Instrumental Analysis’, D A Skoog, F J Holler and T A Nieman, 5th Edition, Thomson Learning, Crawfordsville, 1998.