Paper chromatography its types and applications...

CHROMATOGRAPHY IN DETAIL

1. Introduction and definition of chromatography and paper chromatography

2. Chromatography:- Chromatography was first devised in Russia by the Italian-born scientist Mikhail Tsvet in 1900. In the first decade of the 20th century, primarily for the separation of plant pigments . Chromatography technique developed substantially as a result of the work of Archer John Porter Martin and Richard Laurence Millington Synge during the 1940s and 1950s, for which they won the 1952 Nobel Prize in Chemistry

3. Definition :- Chromatography is a process for separating components of a mixture. ... The different components of the mixture travel through the stationary phase at different speeds, causing them to separate from one another. As a result, he named the technique “ chromatography ”; “chroma” from the Greek word for “color”, combined with “graphy”, meaning writing. In all chromatography there is a mobile phase and a stationary phase . The stationary phase is the phase that doesn't move and the mobile phase is the phase that does move. The mobile phase moves through the stationary phase picking up the compounds to be tested.

4. Paper chromatography The discovery of paper chromatography in 1943 by Martin and Synge provided, for the first time, the means of surveying constituents of plants and for their separation and identification. There was an explosion of activity in this field after 1945. Paper chromatography , in analytical chemistry, technique for separating dissolved chemical substances by taking advantage of their different rates of migration across sheets of paper . It is an inexpensive but powerful analytical tool that requires very small quantities of material.

5. Principal of paper chromatography The principle involved can be partition chromatography or adsorption chromatography. Partition chromatography because the substances are partitioned or distributed between liquid phases. The two phases are water held in pores of the filter paper and the other phase is a mobile phase which passes through the paper.

6. 1-Paper partition chromatography The principle involved is partition chromatography wherein the substances are distributed or partitioned between liquid phases. One phase is the water, which is held in the pores of the filter paper used; and other is the mobile phase which moves over the paper. The compounds in the mixture get separated due to differences in their affinity towards water (in stationary phase) and mobile phase solvents during the movement of mobile phase under the capillary action of pores in the paper .

7. 2-Paper absorption Chromatography The principle can also be adsorption chromatography between solid and liquid phases, wherein the stationary phase is the solid surface of the paper and the liquid phase is of the mobile phase. But most of the applications of paper chromatography work on the principle of partition chromatography, i.e., partitioned between to liquid phases.

8. Application of paper chromatography Separating colored pigments Reaction Monitoring Isolation and Purification Pathology and Forensic Science Foods

9. Analyzing complex mixtures Qualitative analysis C o n t i nu e …

10. phases of chromatography : 1. Mobile phase: The mobile phase is The phase which flow from chromatographic mediaum Generally the mixture to be separated is desolve in a mobile phase. Also it passes through the structure of chromatography Holding the material is called stationary phase. Differential migration is the Principal of chromatography.Different components Of mixture treval at different speed based on the differential interaction to ward mobile phase or stationary phase.

11. The mobile phase Chromatography Can be either liquid or gas. For instance Liquid chromatography is the type of chromatography which use liquid mobile phase. On the other hand,gas chromatography is the type of chromatography which Use gas Mobile phase.

12. 2.Stationary phase Stationary phase is the type of Phase which is fixed Into a column. Hance a polar stationary phase Is used in The forward phase Chromatography While non polar is used in reverse phase. Stationary phase is over which the mobile phase passes the technique of chromatography. Mobile phase is flows through column. The sample is separated injected At the beginning of the column and transported through the system by mobile phase.

13. Procedure Take a paper which is moist. Side selection as a base and line 1 to 2cm above the edge using pencil. Take a capillary tube and will spot this particular line. Leave stationary phase which is actually spotted stationary phase aside to become dry.

14. Continue… Take a chamber and closed the upper part of the chamber .In this chamber we take a solvent. The solvent is then evaporate and dispersed in the entire chamber. Take a stationary phase out and find the Rf “retardation factor”. Calculate the Rf values of the particular component by using the formula.

15. Fo r m ul a Rf = 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑚𝑜𝑣𝑒𝑑 𝑏𝑦𝑠𝑜𝑙𝑢𝑡𝑒 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑟𝑎𝑣𝑒𝑙𝑙𝑒𝑑 𝑏𝑦 𝑠𝑜𝑙𝑣𝑒𝑛𝑡 Let Suppose Distance travelled by solvent front =10cm Distance travelled by component A=2cm Distance travelled by component B=4cm Distance travelled by component C=6cm Distance travelled by component D=8cm

16. Continue… Rf of component A = 2 10 =0.2 Rf of component B = 4 10 =0.4 Rf of component C = 6 10 =0.6 Rf of component D = 8 10 = 0.8

17. Descending paper chromatography W hen the development of the paper is done by allowing the solvent to travel down the paper it is known as descending techniques.

18. Ascending paper chromatography W hen the development of the paper is done by allowing the solvent to travel up the paper it is known as ascending techniques. Both ascending and descending techniques have been employed for speration of organic and inorganic substances. But the ascending techniques is Perffered if Rf value of constitution Are almost same.

19. Ascending descending paper chromatography It is the hybrid of the above two techniques in this techniques the upper part of the ascending chromatography can be folded over a glass rod allowing the ascending development to change over into the descending after crossing the glass rod.

20. Two dimensional chromatography In this techniques a square rectangular paper is used . The samples is applied to one of the corner. The second development is performed at the right angle to the direction of the first run. This type of chromatography can be carried out with identical solvent system in both the direction or by two solvent.

21. Radial paper chromatography This is also known as circular paper chromatography . This make use of radial development. In this techniques a circular filter paper is employed. Then the various material to be analyzed are placed at the center . After drying the spot the paper is fixed horizontally on the petri dish possessing the solvent so the tounge or the wick. W hen the solvent front has moved through a sufficient large distance the components get sperated in the from of concentric circular zones.