Caffeine can be extracted from tea sweepings, coffee roaster,tea dust or tea. caffeine is white in colour or white powder.it is anhydrous or on hydration only one molecule of water will be attached. it is bitter, needle shape,sublimined crystals. In the presence of salicylate citric acid, benzoates it's solubility in water increases very much.
ISOLATION OF CAFFEINE:
Around 50 gram of tea powder are taken and extracted with alcohol for around 6 hours in soxhlet extractor. The extract is transferred into procelain dish which already contain magnesium oxide. Heat it on steam bath with continuous stirring and evaporate it. Boil the obtaine residue three times with 100 ml water. Filter it in hot condition through buchner funnel. Add the 10% sulphuric acid in combined filtrate. Concentrate the above filtrate to one third of volume. Filter the solution when hot and extract it with 5 times with chloroform. Add sodium hydroxide in chloroform extract so that the decolorisation takes place, Equal quantity of water is added in this and separate the chloroform layer. Evaporate the chloroform extract to obtain crude caffeine which can be recrystallized with hot water.
Caffeine can be also extracted by super critical fluid extraction technique by using liquefied carbon dioxide.liquefied carbon dioxide absorbs the caffeine through moist coffee. then it is passed through another pressurized vessel containing absorbing media like resin or activated carbon which retain the caffeine. Separate this caffeine by extracting with chloroform.
THIN LAYER CHROMATOGRAPHY OF CAFFEINE:
Dissolve caffeine (1 mg ) in chloroform (1 ml) or methanol.then spot the sample on TLC plates and eluted in solvent system ethyl acetate: methanol: acetic acid (8:1:1). Then visualize the spots on dried TLC plate by exposure to iodine vapour. The Rf value was 0.41.
IDENTIFICATION TEST:
Murexide test:
Caffeine or purine derivatives is detected by mixing with a very small amount of potassium chlorate and a drop of Hcl. Evaporating to dryness and exposing the residue to ammonia vapour. A purple colour is produced with caffeine and other purine derivatives.
Medical uses of caffeine
Caffeine is used to treat intermittent pauses in breathing (apnea) in premature infants. Addition of caffeine to commonly prescribed pain relievers (such as acetaminophen) can decrease acute pain from certain conditions, such as migraines.
Common negative effect for caffeine:
Caffeine leads to temporary increases in blood pressure in individuals with minimal or no prior use. Caffeine, particularly in higher doses, can cause anxiety, as well as difficulty falling asleep if consumed late in the day. Abrupt cessation of caffeine in regular users may result in withdrawal symptoms, which typically peak at 1 to 2 days and include headache, fatigue, and depressed mood. Because higher caffeine intake in pregnancy is associated with lower infant birth weight, caffeine consumption should not exceed 200 mg per day during pregnancy.
Effects of Caffeine in Very High Doses
Ingestion of very high doses of caffeine (1200 mg or more) can cause agitation, severe anxiety, elevated blood pressure, and palpitations. This may occur with overuse of caffeine tablets or supplements in liquid form (energy drinks) or powdered form. Consuming caffeinated energy drinks or energy shots together with alcohol is dangerous and has resulted in deaths.
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