ST. MARY’S CONVENT SCHOOL GAJRAULA Project file

NAME : SHARAD KUMAR

CLASS : 12 B ROLL NO : 27

SUBJECT: CHEMSTRY

TOPIC : determination of caffeine in Tea sample

Submitted to : ma’am mamta saini

Submitted by : sharad kumar

First of all I would like to thank my friend Nimish Agarwal my classmate, for his contribution in this

study.

I would also like to thank my ChemistryTeacher Mrs.Mamta Saini in providing a helping hand inmaking my project titled “Determination OfCaffeine In Tea Samples”.Disclaimers: The errors idiocies and inconsistenciesremain my own.

Sharad Kumar

it is hereby certify that, theoriginal and genuine researchwork is carried out to investigateabut the subject matter and therelated data collection and has

been completed solely andsatisfactorily by this studentregarding the Project titled

“Determination Of Caffeine In TeaSamples”.

Signature(subject teacher)

1. Certificate 2. Acknowledgement3. Introduction4. Theory5. Uses of Caffeine

6. Effects of Caffeine7. Procedure8. Observations9. Result10. Bibliography

Tea is the most commonly and widely usedsoft beverage in the household. It acts as astimulant for central nervous system andskeletal muscles. That is why tea removesfatigue, tiredness and headache. It alsoincreases the capacity of thinking. It is alsoused for lowering body temperature. Theprincipal constituent of tea, which isresponsible for all these properties, is thealkaloid-caffeine. The amount of caffeine in

tea leavers varies from sample to sample.Originally it was thought that caffeine isresponsible for the taste and flavour of tea.But pure caffeine has been found to be atasteless while substance. Therefore, thetaste and flavour of tea is due to some othersubstance present in it. There is a littledoubt that the popularity of the xanthenesbeverages depends on their stimulantaction, although most people are unaware of any stimulation. The degree to which an individual is stimulated by given amount ofcaffeine varies from individual toindividual.The xanthene beverages also create amedical problem. They are dietary of astimulant of the CNS. Often the physiciansface the question whether to deny caffeine containing beverages to patients or not. Infact children are more susceptible thanadults to excitation by xanthenes. For this reason, tea and coffee should be excluded from their diet. Even cocoa is of doubtful value. 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 differentsamples of tea leaves.

The most important methylated alkaloidthat occurs naturally is caffeine. Itsmolecular formula is C8H10N4O2. Its IUPACname is 1, 3, 7-trimethylxanthene and

common name is 1-methylated thiobromine.

Purely it is white, crystalline solid in theform of needles. Its melting point is 1230c. Itis the main active principle component oftea leaves. It is present in tea leaves up to3% and can be extracted by first boiling thetea leaves with water which dissolves many

glycoside compounds in addition tocaffeine. The clear solution is then treatedwith lead acetate to precipitate theglycoside compounds in the form of leadcomplex. The clear filtrate is then extractedwith extracts caffeine because it is moresoluble in it then water.

1. In medicine, it is used to stimulate,central nervous system and to increaseflow of urine.

2. Because of its stimulating effects,caffeine has been used to relieve fatigue.But it is dangerous and one maycollapse if not consumes it under certainlimit.

3. Caffeine is also used in analgesictablets, as it is believed to be a painreliever. It is also beneficial inmigraines.

1. It is psycho - stimulant.

2. It improves physical and mental ability.

3. Its effect in learning is doubtful butintellectual performance may improvewhere it has been used to reduce fatigueor boredom.

4. When administered internally, itstimulates heart and nervous systemand also acts as diuretic. On thecontrary their excessive use is harmfulto digestion and their long use leads tomental retardation.

First of all, 50 grams of tea leaveswere taken as sample and 150 ml ofwater was added to it in a beaker.

Then the beaker was heated up to

extreme boiling.

The solution was filtered and leadacetate was added to the filtrater,leading to the formation of a curdybrown coloured precipitate.

We kept on adding lead acetate till nomore precipitate has been formed.

Again solution was filtered.

Now the filtrate so obtained wasThen the solution left was allowed tocool.

After that, 20 ml. of chloroform wasadded to it.Soon after, two layers appeared in the separating funnel.

We separated 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 theobservations.

Similar procedure was performed withdifferent samples of tealeaves and quantityof caffeine was observed in them.

1.Red Label Tea (Brooke Bond)Weight of china dish= 46.60 gm.Weight of china dish with precipitate = 47.20gm.Amount of caffeine= 0.60 gm.

2.Yellow Label Tea (Lipton)Weight of china dish= 46.60 gm.Weight of china dish with precipitate = 47.15 gm.Amount of caffeine= 0.55 gm.

3.Green Label Tea (Lipton)Weight of china dish =46.60 gm.Weight of china dish with precipitate = 47.05 gm.Amount of caffeine= 0.45 gm.

Quantity of caffeine in Red label

tea is 60mg. /sample of 50 gm.

Quantity of caffeine in yellow label tea is 55mg./sample of

50 gm.

Quantity of caffeine in green label

tea is 45mg./sample of 50 gm.

Bibliographywww.google.com

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