05-02-2013, 02:17 PM
Determination of caffeine in different samples of tea
Determination of caffeine.ppt (Size: 785 KB / Downloads: 57)
Introduction
Tea is the most commonly and widely used beverage in the house hold.. It acts as a stimulant for central nervous system and skeletal muscles. That’s why tea removes fatigue, tiredness and headache. It also increases the capacity of thinking. It is also used for lowering body temperature. The principal constituent of tea, which is responsible for all these properties is the alkaloid caffeine
Caffeine
Originally, it was thought that caffeine is responsible for the taste of tea. But pure caffeine has been found to be a tasteless white substance. Therefore, the taste & flavor of tea isd due to some other substance present in it. There is a little doubt that the popularity of the xanthene beverages depends on their stimulant action, although most people are unaware of any stimulation. The degree to which an individual is stimulated by given amount of caffeine varies form individual to individual.
Uses of caffeine
In medicine, it is used to stimulate central nervous system and to increase flow of urine
Caffeine has been used to relieve fatigue. But it is dangerous and one may collapse if not consumes it under certain limit
Caffeine is also used in analgesic tablets, as it is believed to be pain reliever
It is beneficial in migraines.
Effects of caffeine
It is a psycho stimulant
It improves physical and mental ability
Its effect in learning is doubtful but intellectual performance may improve where it has been used to reduce fatigue or boredom
When administered internally, it stimulates heart and nervous system and also acts as diuretic. On the contrary their excessive use is harmful to digestion and their long use leads to mental retardation.
Procedure:
First of all, 50 grams of tea leaves were taken as sampe and 150 ml of water was added to it in a beaker
Then the beaker was heated up to extreme boiling
The solution was filtered and lead acetate was added to the filtrate , leading to the formation of a curdy brown colored precipitate.
We kept on adding lead acetate till no more precipitate has been formed
Again solution was filtered