Tea Chromatography

According to the results, the columns of caffeine in figure 1, of this experiment the hypothesis for caffeine is partially accepted. There is an increasing trend in the change of pulsation rates with increasing

Caffeine is a mild stimulant that occurs naturally in at least 63 plant species. Caffeine can be found in the leaves, stems, seeds, and roots of these various plants. Caffeine is part of the methylxanthine family. It consists of a xanthine molecule with three methyl groups attached to it. Caffeine can be found in many products like sodas, tea, and coffee, but it also occurs in several other products such as prescription medications, diuretics, and pain relievers. Caffeine’s widespread use and popularity have caused many people to view the substance as an addictive drug. Thus making caffeine the most inexpensive and readily available drug known to man. Then on the other hand there are

Caffeine is a photoactive stimulant found in plant species. These plant species vary including tea, coffee and cocoa. The caffeine is absorbed fully into the stomach and small intestine after 30 to 45 minutes, which is the peak of the caffeine. The caffeine is in a person’s body for up to 4 hours. Caffeine has consequences if over dosed. Anxiety, heart palpitations, headaches, insomnia and nervousness are all physical and mental conditions that can be present if you have caffeinism. This research gives me an insight into caffeine I would have never known if I did not chose this topic to study.

Many manufactures release the caffeine content of their products publically, but not always, and new products and flavors are continuously introduced to the market. If quality checks are not performed, manufactures may alter the caffeine and benzoic acid content to suit the demands without public knowledge. To ensure the levels of caffeine and benzoic acid in products do not exceed the established safe limits and to inform the public of the amount of these compounds being consumed, various methods of analysis have been performed. Before the introduction of modern techniques, spectrophotometric methods alone were used to determine concentration of a compound in a mixture.6 The caffeine content in coffee, tea, soft drink, and energy drinks were determined using an immunoassay.7 The caffeine content in mixtures also used to have to be extracted before quantification.8

1) Adding sodium carbonate was the step in the reaction that prevented the extraction of acidic organic impurities from the tea solution. The carbonate ion reacts with acidic compounds to form H2CO3, it’s conjugate acid. The carbonic acid (H2CO3) can then go on to form carbon dioxide and water. 2) A - If you did not use sodium carbonate to remove the organic impurities, then this would have a positive systematic error affect on the final mass of the collected caffeine. This means that adding sodium carbonate prevents the extraction of these impurities, which would decrease the final collected mass and its acidic components.

First, saturate the TLC trough with 30 ml of ethyl acetate: methanol solution for 10 mins. Next, spread the silica gel into into a 0.2 micrometer film over the Aluminum plate. Then, to dry the plate for usage, heat the plates in an oven at 110 Celsius for 5 min. Apply the samples 1 cm above the base of the plate using a sample applicator, along with nitrogen gas to allow the bands to simultaneously dry. Place the TLC Plate into the chromatography trough, and allow the plate to develop until the 10cm mark. Follow up by scanning the TLC plate in a densitometer to obtain a chromatogram of the separated samples. The Peak of caffeine observed on the chromatogram can be matched to the real plate and be scraped off for the retrieval of caffeine.

In this experiment 10.0514 g of espresso yielded 1.1178 % of crude caffeine. The average data of caffeine from black tea with the average weight of 9.5195 g had a 3.60% yield of caffeine. The average data of coffee with the average weight of 9.5306 g had an average yield of 1.4875% crude caffeine. The average data of espresso with the average weight of 9.4636 g had an average yield of 4.19% crude caffeine. The green tea with a weight of 9.6489 g had a yield of 2.4022% crude caffeine. According to Caffeine Content, the average caffeine content of regular coffee is 13.5 mg per gram of coffee, which means the crude caffeine recovery yield would be 1.35% (Coffee's Caffeine). The caffeine informer sates that green tea has about 10-20 mg of caffeine per 1 gram of leaves meaning that it has recovery yield of about 1-2% crude caffeine, and black tea has about 22-28mg of caffeine per 1 gram dried matter giving a recovery yield of about 2.2% -2.8% (Caffeine informer).

Part B tested solutes 1-butanol, 1-octanol, and methanol for their solubility in water and hexane separately. Part C tested dichloromethane (Methylene chloride), diethyl ether, hexane and water for their immiscibility in four different probable combinations. As for extraction , Part A of the experiment tested the ability to use a separatory funnel, 3 times of methylene chloride as the solvent and anhydrous sodium sulfate as the drying agent that would formulate an ultimate yield percentage to extract caffeine form and aqueous solution.[2] Part B of the experiment used a similar method of extraction as Part A (drying and evaporation) to test how benzoic acid (solute) distributes between methylene chloride and water (immiscible solvents) so as to develop an ultimate calculation of the “distribution coefficient of the solid between the two layers. ”[3] The constant (K) is the distribution coefficient determining the concentration ratios at the equilibrium reached after a solution is placed in two immiscible solvents.

Extraction is a valuable technique to use when withdrawing a desired substance from a mixture of chemical substances. As a rule, the top layer is less dense than the bottom layer. In this experiment, impurities such as chlorophyll, cellulose, and flavornoids are in the top aqueous layer and caffeine is the bottom organic layer. Chlorophylls, flavornoids, and their oxidation products, are what gives tea solutions their brown pigmentation. However, only chlorophylls are soluble in the dichloromethane and give caffeine a green color. Cellulose is an almost insoluble polymer of glucose. Caffeine is a known water-soluble compound, however, caffeine is more soluble in dichloromethane. According to Chemicalbook, caffeine’s solubility

In this laboratory, freshly brewed green tea and bottled carbonated green tea were used to compare caffeine peaks. The experiment was divided into three weeks. In week one, a calibration curve and the determination of an unknown sample were the done by preparing a series of caffeine standard solutions. A calibration curve is often used to determine the concentration of a component in an unknown sample by comparing the unknown to a set of standard samples of known standard concentration (3). On week two, the one point calibration method was used to determine the caffeine concentration of a freshly brewed green tea bag diluted in water.

The molecular formula for caffeine is C8H10N4O2 and it is chemically classified in the xanthine group.1 It was first discovered and isolated by Friedrich Ferdinand Runge, a German chemist in 1819. Once this element is isolated and purified, it is bitter white powder. This purified caffeine is added to drinks such as soft drinks, colas and energy drinks. Caffeine is found in many different plants such as coffee beans, cacao beans and tea where it paralyses and kills bugs that pursue the plants, acting as a natural pesticide. Caffeine has many effects on the body; including a short burst of energy, acting in a similar way to the hormone adrenaline and surprisingly, cocaine.6 Although it has some good effects, negative effects can occur from excessive intake.

Caffeine is one of the most well-known orally consumed drug around the world. In the 1820s, a German chemist named Friedrich Ferdinand Runge first discovered caffeine by extracting it from coffee [6]. Coffee and tea are leading sources of caffeine in the adult diet whereas caffeinated soft drinks are leading sources of caffeine in the diet of children in North America [7]. The per capita consumption level of caffeine for consumers of all ages is approximately 120mg/day [4]. The purpose of this investigation is to conclude whether the regular consumption of caffeine is beneficial to human health.

From the journal of Core Concepts in Pharmacology, Holland and Adams (2007) have stated that Caffeine is a natural substance found in the seeds, leaves, or fruits of more than 63 plant species. Significant amounts of caffeine are consumed in coffee, chocolate, soft drinks and tea. Sometimes caffeine is added to over the counter pain relievers to help relieve migraines and other conditions. Caffeine travels to almost all parts of the body after ingestion, and several hours are needed for the body to metabolize and eliminate the drug. Caffeine is considered a central nervous system stimulant because it produces increased mental alertness, restlessness, nervousness, irritability and insomnia. The physical effects of caffeine include bronchodilation, increased blood pressure, increased production of stomach acid , and changes in blood glucose levels. Repeated use of caffeine may result in physical dependence and tolerance. The serving size of a brewed and instant coffee is 8 ounces and containing 95 to 135mg of caffeine while the serving size for decaffeinated coffee is 8 ounces containing 5mg.

In this experiment, the effectiveness of an extraction process and purification process by sublimation is observed and used to selectively separate caffeine from teabags. In the first part of the experiment, water soluble materials, including caffeine, within the teabags are extracted into hot water because the solubility of caffeine in water increases as temperature increases. This is due to the concept that increasing kinetic energy through increasing temperature will allow the molecules in the solute to break apart from the intermolecular interactions more effectively. Afterwards, the solution was filtered using a Buchner funnel to remove any solids from the liquid solution containing the caffeine. Then, the solution is allowed to cool before the caffeine to be extracted from the water by using methylene chloride, sodium chloride, and anhydrous sodium sulfate as part of a liquid-liquid extraction work up. Specifically, this liquid-liquid extraction distributes the caffeine into two solvents, methylene chloride and water, which are insoluble and immiscible to each other. By using density, solubility, and polarity differences of a solute in a pair of solvents, the organic compound of interest can be transferred from one liquid phase to the other during an extraction. Since the two solvents used are insoluble and immiscible to each other, two layers, the organic layer and the aqueous layer, will form and can be extracted to obtain the caffeine. Since caffeine is nonpolar,

Caffeine is a xanthine alkaloid compound, whose use dates back to the stone age. It appears as a white, odorless, glistening powder in its