The document discusses paper chromatography, a technique used to separate mixtures and identify their components. It explains the basic procedures, which involve spotting a sample onto a pencil line on chromatography paper, then developing the chromatogram by allowing a solvent to travel up the paper. This causes the different components in the mixture to travel different distances based on their solubility and adsorption to the paper, resulting in separated spots that can be used to identify the components. Paper chromatography is useful for analyzing mixtures like dyes, inks, and drugs, and allows for testing purity by observing the number of spots produced.

1. Purification of Substances Highlight!! Sneak preview of our first session included!!

6. Examples: dyes , food colorings, forensics, Urine analysis etc. Paper Chromatography Solvent Solvent front Paper Lid Resolved spots

9. Paper Chromatography – PROCEDURE 1 At the Start At the End Chromatogram

16. Paper Chromatography – PRINCIPLE 1

18. THREE KINDS OF CHROMATOGRAMS THAT CAN BE DEVELOPED

22. Which of the soft drinks contain a harmful dye? A) P and Q B) R and S C) Q and S D) P and R P Q R S X Y soft drinks dyes Interpreting Chromatograms

24. chromatography What happen if there are more than 20 suspected substances in the sample? It would not be practical to put all the suspected substances on the chromatogram. We can make use of the R f values.

26. Chromatography A B B A Solvent used : alcohol

28. Applications: Chromatography Detection of - drugs in athletes - pesticides sprayed on vegetables - illegal dyes in food

30. Drugs have provided the world of athletics with a fierce opponent ever since the emergence of systematic forms of doping in eastern Europe. But the most famous case in history is that involving a westerner - Canadian sprinter Ben Johnson. He won the 100 metres at the 1988 Seoul Olympics in a world record time but was later stripped of his gold medal and banned for two years after testing positive for an anabolic steroid. Since then he has made an unsuccessful attempt to get back into the Canadian team for the 2000 Olympics. There have also been some bizarre stunts such as a race with two horses and car for charity. The animals beat him although the car was stalled by wheelspin. Johnson has recently worked as personal fitness trainer for footballer Said Gaddafi, son of Libyan president Colonel Muamar Gadaffi. Meanwhile an incident in which a mugger took his wallet and outran him showed that the 38-year-old does not have the speed he once possessed. Drugs in world athletics BBC Sport website (Mon 31 July 2000) Tainted win: Johnson (second left) wins in Seoul A life ban from the track followed in March 1993 when he gave another positive test.

32. The Straits Times, 7 December 1988