project on determination of caffeine in tea samples

Today we will see how to make project on 'project on determination of caffeine in tea samples' this project is only for class 12th student and this project is belongs to 'chemistry' in this project we will cover following steps

♦️ Introduction

♦️ Theory 

             a) Caffeine
            b) Uses of caffeine
            c) Effects of Caffeine

♦️ Material Required

♦️ Procedure

♦️ Observations


♦️ Result

♦️ Bibliography

                  INTRODUCTION

Tea is the most commonly and widely used soft beverage in the household. It acts as a stimulant for central nervous
system and skeletal muscles. That is why tea removes fatigue, tiredness and headache. It is also used for lowering body temperature. The principal constituent of tea, which is responsible for all these properties, is the alkaloid-caffeine. The amount of caffeine in tea leavers varies from sample to sample. Pure caffeine has been found to be a tasteless substance.
The xanthene beverages found in tea also create a medical problem. Often the physicians face the question whether to
deny caffeine-containing beverages to patients or not. In fact children are more susceptible than adults to excitation by xanthene.
For this reason, tea and coffee should be excluded from their diet. It has a high tannin content may be as high as 50 mg
per cup. After all our main stress is on the presence of caffeine in xanthene beverages and so in this project we will
study and observe the quantity of caffeine varying in different samples of tea leaves.

                                 Theory

Caffeine

The most important methylated alkaloid that occurs naturally is caffeine. Its molecular formula is C8H10N4O2. Its IUPAC name is 1, 3, 7-trimethylxanthene and common name is 1- ethylated thiobromine

                                     

Purely it is white, crystalline solid in the form of needles. Its melting point is 1230c. It is the main active principle component of tea leaves.

Uses of Caffeine

In medicine, it is used to stimulate, central nervous system and to increase flow of urine.

Because of its stimulating effects, 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 a pain reliever. It is also beneficial in migraines.

Effects of Caffeine

It is 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 sample 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 filtrater, leading to the formation of a curdy brown coloured precipitate.

⇒ We kept on adding lead acetate till no more precipitate has been formed.

⇒ Again solution was filtered.

⇒ Now the filtrate so obtained was heated until it had become 50 ml.

⇒Then the solution left was allowed to cool.

⇒After that, 20 ml. of chloroform was added to it.

⇒ Soon after, two layers appeared in the separating funnel.

⇒Now separate the lower layer.

⇒The solution then exposed to atmosphere in order to allow

chloroform to get evaporated.

⇒The residue left behind was caffeine.

⇒ Then we weighed it and recorded the observations.

Similar procedure was performed with different samples of tea leaves and quantity of caffeine was observed in them.

                     OBSERVATION

1. Red Label Tea (Brooke Bond)

2. Yellow Label Tea (Lipton)

3. Green Label Tea (Lipton)

                        RESULTS

Quantity of caffeine

Red label tea - 60mg. /sample of 50 gm.

Yellow label tea - 55mg./sample of 50 gm.

Green label tea - 45mg./sample of 50 gm.

Percentage of caffeine

Red label tea – 0.12%

Yellow label tea – 0.11%

Green label tea – 0.9%

                Bibliography

♦️ Wikipedia -the free encyclopedia

♦️ https://www.caffeineinformer.com/caffeine-content/tea-brewed

♦️ http://www.mayoclinic.org/healthy-lifestyle/nutrition-andhealthy-

♦️ eating/in-depth/caffeine/art-20049372?pg=2

♦️ http://www.theteaspot.com/about-tea.html

♦️ allaboutjiophone-org.webnode.com

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