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  • 8/12/2019 Science Chemistry Main


    Know How much caffeine you aretaking in with each cup of tea!

    Project Prepared By:

    Jijo k eype

    XII-ScienceRoll Number:17GGIS
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    First of all I would like to thank my brother Mr.Praveen for his contribution in this study. I wouldalso like to thank my Chemistry Teacher Ms. Dhruvimam in providing a helping hand in making my

    project titled Determination Of Caffeine In Tea


    Disclaimers: The errors and inconsistencies remainmy own.

    Jijo k Eype
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    It is hereby certify that, the originaland genuine research work is carried

    out to investigate abut the subjectmatter and the related data collection

    and has been completed solely andsatisfactorily by this studentregarding the Project titled

    Determination Of Caffeine In TeaSamples.

    Signature(Subject Teacher)
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    1. Introduction2. Theory3. Uses of Caffeine4. Effects of Caffeine

    5. Procedure6. Observations7. Result
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    Tea is the most commonly and widely usedsoft beverage in the household. It acts as astimulant for central nervous system and

    skeletal 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 intea 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 a

    tasteless 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 stimulant

    action, although most people are unaware
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    of any stimulation. The degree to which anindividual is stimulated by given amount of

    caffeine varies from individual toindividual.

    For example, some people boast theirability to drink several cups of coffee inevening and yet sleep like a long, on the

    other hand there are people who are sosensitive to caffeine that even a single cupof coffee will cause a response boarding onthe toxic.

    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 than

    adults to excitation by xanthenes.

    For this reason, tea and coffee should beexcluded from their diet. Even cocoa is of
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    doubtful value. It has a high tannin contentmay be as high as 50 mg per cup.

    After all our main stress is on the presenceof caffeine in xanthenebeverages and so inthis project we will study and observe thequantity of caffeine varying in differentsamples of tea leaves.
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    The most important methylated alkaloidthat occurs naturally is caffeine. Itsmolecular formula is C8H10N4O2. Its IUPACname is 1, 3, 7-trimethylxanthene andcommon name is 1-methylatedthiobromine.
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    Purely it is white, crystalline solid in theform of needles. Its melting point is 1230c. It

    is 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 manyglycoside compounds in addition tocaffeine. The clear solution is then treated

    with 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.
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    Uses of Caffeine:

    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 pain

    reliever. It is also beneficial inmigraines.
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    Effects of Caffeine

    1. It is psycho - stimulant.2. It improves physical and mental ability.3. Its effect in learning is doubtful but

    intellectual performance may improvewhere it has been used to reduce fatigue

    or boredom.4. When administered internally, it

    stimulates heart and nervous systemand also acts as diuretic. On thecontrary their excessive use is harmfulto digestion and their long use leads to

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

    Then the beaker was heated up toextreme 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 was

    heated until it had become 50 ml.

    Then the solution left was allowed tocool.

    After that, 20 ml. of chloroform wasadded to it.

    Soon after, two layers appeared in theseparating funnel.
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    We separated the lower layer. The solution then exposed to

    atmosphere in order to allowchloroform 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
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    1. Red Label Tea (Brooke Bond)

    Weight of china dish 46.60gms

    eight of china dishwith precipitate


    Amount of caffeine 0.60gms

    2222.... Yellow Label Tea (Lipton)Yellow Label Tea (Lipton)Yellow Label Tea (Lipton)Yellow Label Tea (Lipton)

    Weight of china dish 46.60gmseight of china dish

    with precipitate47.15gms.

    Amount of caffeine 0.55gms
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    3. Green Label Tea (Lipton)3. Green Label Tea (Lipton)3. Green Label Tea (Lipton)3. Green Label Tea (Lipton)

    Weight of china dish 46.60gms.

    eight of china dishwith precipitate


    Amount of caffeine 0.45gms.

    1. Quantity of caffeine in Red label teais 60mg. /sample of 50 gm.

    2. Quantity of caffeine in yellow label tea is 55mg./sample of 50 gm.

    3. Quantity of caffeine in green label teais 45mg./sample of 50 gm.
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