Comparison between Single and Multiple Extraction E xtraction of Caffeine from Dried Tea Leaves
ADMC, PMMC, LAC, AKC, RMC, LJMD 2A-Pharmacy, Faculty of Pharmacy, University of Santo Tomas
Abstract Extraction is a process or separating two immiscible liquids. With the use of dried tea leaves, caffeine was separated with the use of extraction. Anhydrous sodium carbonate yielded to a purer caffeine during the extraction. In separating the organic and the aqueous layer, dichloromethane was introduced and mixed slowly with the extract. After the two layers were separated, anhydrous sodium sulphate was added to remove the impurities and was left to decant and evaporate to dryness. The caffeine was weighed after and the percentage caffeine was calculated. The single and multiple extraction was compared and showed that multiple extraction has an advantage over single extraction. I.
Introduction Extraction is the process of separating two immiscible liquids consisting of the organic and the aqueous layer. Immiscible liquids meaning they will separate or they cannot be mixed. There are two types of extraction, the single and multiple extraction. [1] Extraction has always been very helpful to humankind especially to everyday living. Also, extraction is primarily essential in the field of science and pharmacy. pharmacy. Though extraction has disadvantages disadvantages like inconsistency inconsistency in the composition of the extract, by the time of Serturner, it has flourished and been very useful. Just like the extraction of morphine from opium which is now very useful to the field of medicine. After Serturner’s experiment, many other experiment about extraction followed and prospered the field of chemistry as well as pharmaceutical chemistry. Now, several studies are still conducted finding sources of potential drugs and compounds. [2] Teas and coffees have been a popular drink even decades before probably because of a [3] stimulant called caffeine. Caffeine is naturally occurring and can be found in tea leaves and coffee beans. Several energy drinks also use caffeine. It is classified as an alkaloid, a nitrogen-containing nitrogen-containing basic [4] compound. Caffeine is used as a stimulant and can be addictive. In this experiment, single and multiple extraction of caffeine from dried tea leaves will be performed and and compared compared and the percentage percentage yield of of caffeine in both extractions extractions will be calculated calculated.. II.
Materials and Method In order to extract caffeine, dried tea leaves were needed and Lipton Yellow Tea was specifically used. For the extraction, hot plate, beaker, tea leaves and the anhydrous sodium carbonate were used. Dichloromethane was introduced to separate the organic layer from the aqueous layer. With the use of a iron stand, iron ring, iron clamp and a separatory funnel, the organic layer was able to be separated from the aqueous layer. Lastly, in a Erlenmayer flask, sodium sulphate was added to the organic layer. In a small Erlenmayer flask, 4.4 g of anhydrous sodium carbonate was placed together with 100mL of distilled water. The solution was heated using a water bath until the solid dissolves. 10 g of tea leaves in a teabag was placed into the mixture. The mixture was covered and boiled for 10 minutes on a low flame. After the tea extract was fully removed from the teabags by squeezing using a glass rod, the teabags were discarded. For single extraction, 60 mL of dichloromethane was placed in a separatory funnel and mixed slowly with the tea extract. The mixture was left to stand for two minutes or until there is a clear separation between the two liquids. If there was a bubbling it was removed using a glass rod. The organic layer was drained into a clean Erlenmayer flask and the aqueous layer was discarded. For multiple extraction, the aqueous solution was slowly mixed with 20 mL dichloromethane for three times in each separation. It was left to stand for two minutes until there is a clear separation between the liquids.
Figure No. 1. Extraction Setup and the Proper way of Mixing Dichloromethane and Tea Extract The aqueous layer was discarded and the organic layer extracts were combine. Half a spatula of anhydrous sodium sulphate was added to the extract then decanted into a tared evaporating dish. The mixture was evaporated to dryness for two days. After the residue was weighed, percentage yield was calculated.
Figure No. 2. Extracted Caffeine from Dried Tea Leaves
Figure No. 3. Percentage Yield Formula III.
Results and Discussion Group No. % Caffeine 1 9 3 3 5 10 7 4 9 2 Average 5.6 Table No. 1. Percent Caffeine for each Single Extraction the Average Percent Caffeine
Group No. % Caffeine 2 5 4 10 6 3 8 6.8 Average 6.2 Table No. 2. Percent Caffeine for each Multiple Extraction and the Average Percent Caffeine
Extraction is only possible with two immiscible liquids meaning not forming a homogenous mixture when added together. In the experiment, a pre-weighed evaporating dish was prepared in order to weigh the caffeine. Also, it was required in the experiment to add anhydrous sodium carbonate. The purpose of the anhydrous sodium carbonate is to ensure that the acidic substance remains water soluble and the caffeine will be present as a free base. [3] For the extraction, in a separatory funnel, dichloromethane was added and mixed slowly. This is to ensure that the two layers will be properly separated. In the end, after the aqueous layer was discarded, anhydrous sodium sulphate was added to the organic layer to remove the water and any water soluble salts that are retained in the organic layer. In Table 1 are the percentage recovery of the caffeine for single extraction and on average it only has 5.6 % caffeine which is relatively low compared to the multiple extraction which has an average percent recovery of 6.2%. Based on this, multiple extraction is more advantageous over single extraction. Multiple extraction is more efficient over single extraction. This is because the compounds to be extracted will be reside in the one-phase over the other. Moreover, partition coefficient also known as distribution constant, the relationship between the solubility ratios of the two different compounds is smaller.[5] IV.
References 1. University of Colorado at Boulder, Department of Chemistry and Biochemistry. (2014). Organic Chemistry at CU Boulder . Retrieved from University of Colorado Web site: http://orgchem.colorado.edu/Technique/Procedures/Extraction/Extraction.html 2. Weizman, H.. Extraction and isolation of Caffeine from tea leaves. Retrieved from University of California, San Diego, Chemistry and Biochemistry Department Web site: http://chem-courses.ucsd.edu/CoursePages/Uglabs/143A_Weizman/Lab%20manual.html 3. Cengage Learning. (2012). Techniques labs for macroscale and microscale organic th experiments 6 ed. Brooks/Cole 10 Davis Drive, CA, USA: Williamson, K. and Masters, M.. Retrieved from http://books.google.com.ph/books?id=e7L4lQIC1XgC&printsec=frontcover&source=gbs _ge_summary_r&cad=0#v=onepage&q&f=false 4. Indiana State University, Department of Chemistry and Physics. (2014). Extraction of caffeine. Retrieved from Indiana State University Web site: http://carbon.indstate.edu/inlow/LabManuals/Caffeine.pdf 5. Bunnelle, W. H., Meyer, L. A., Glaser, R. E.. (2014). Extraction. Retrieved from University of Missouri Department of Chemistry Web site: http://www.chem.missouri.edu/chem2050/expt_2.pdf 6. University of Santo Tomas Department of Chemistry. (2014). Laboratory manual in organic chemistry revised edition. Manila. Author
