CHEM368 RICE Caffeine In Various Teas Using Chromatography Methods


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hello, this the comment from prof. don't worry about the reference part I change it by mistake, also, this is the result information for the GC part and the last page from notebook

I will invite you for new assignment to complete the report with all info and make new spread sheet for GC part, I need the spread sheet by Sunday night and the report by the due time of assignment

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Faisal Albukhari Dr. Van Bramer CHEM-368 Testing the Caffeine Concentration in Tea Abstract: The determination of caffeine in coffee is a very important analysis in the pharmaceutical and food industries due to legal restrictions imposed by the FDA. In this experiment, the concentration of caffeine was determined in three Bigelow brand tea samples (earl grey, green, and oolong) and a coffee bean sample using HPLC and GC methods. The HPLC results showed that tea concentrations are less than 15 mg and that green tea has the lowest concentration (6mg). In the case of coffee beans, the mass of caffeine could not be determined due to noise problems in the chromatogram. Introduction: Caffeine is an alkaloid without smell and bitter taste found in many vegetable sources, such as cocoa beans, coffee, tea, among others. Caffeine is widely used in the following industries 1: i) pharmaceutical, for the elaboration of analgesics, anti-flu and diet remedies, ii) food, in the elaboration of energizing and carbonated beverages. It is for this reason, that caffeine has a high global demand (120,000 tons/year) 2. Caffeine can be consumed daily through different sources, such as coffee, tea, chocolate and energy drinks, as well as in anti-migraine drugs 1. The high concentrations of caffeine in living beings can cause a series of disorders related to heart disease, urinary and asthma, and even death (doses >200mg/day) 3. The concentrations of caffeine in beverages as such as coffee and tea may vary depending on the brand; however, the maximum concentrations are well regulated by the FDA and may not exceed 10 g1. Because of legal restrictions, caffeine analysis is of great importance in order to ensure adequate levels in beverages and to comply with regulatory standards. For the analysis of caffeine in beverages, different analytical methods have been used, which may vary depending on the matrix. In the literature, the most recommended techniques are chromatographic and spectroscopic. Chromatographic techniques include high liquid efficiency (HPLC) and gas GC 4. While spectroscopic techniques include UV-visible 5 and FT-IR 6. This study focuses on the analysis of caffeine in tea samples using HPLC and GC techniques to determine if the concentrations of the products used are within the limits established by the FDA. Materials and Method: Sample collection: In this experiment three types of tea (earl grey, green, and oolong) Bigelow brand and a coffee tree leaf from Widener greenhouse were used. The concentration of each sample was determined by two chromatographic methods: LC and GC. LC method: The teas (earl grey, green, and oolong) and the coffee were put in a 300 mL flask and 250 mL of hot water (100 ยฐC) was added. The ingredients were extracted from the tea for 5 minutes. For chromatographic analysis, a column (Discovery RP - AmideC1615 cm x 4.6 mm I.D, 5 um particles) was used, and the mobile phase was prepared with a composition of 75%DI water and 25% methanol (25 mM K2HPO4, pH 7.0). The wavelength used in the UV detector was 254 nm. For the analysis of the standards (10, 20, 50, 70 and 100 ppm of caffeine) and the samples 10ยตL were injected. The running time of the standards and samples was 8 minutes and 30 minutes for samples. GC method: For sample preparation, each tea bag was taken and dissolved in 250 mL of water. Then 20 mL of the dissolved tea was added to a separating funnel. Next, 20 mL of 2-methyl THF was added to the separation funnel, the phases were shaken, so that the extraction of caffeine to the organic phase occurred. We put the injection tubes that contain the standards and samples in the auto samplers and start the GC test. Results and Discussion: The relationship of the areas of the standards with their concentration showed a linear trend with an R2 equal to 0.9992 (Fig. 1). The adjustment obtained was: ๐ด๐‘Ÿ๐‘’๐‘Ž = 140.95 โˆ— ๐ถ๐‘œ๐‘›๐‘๐‘’๐‘›๐‘ก๐‘Ÿ๐‘Ž๐‘ก๐‘–๐‘œ๐‘› + 90.943 Area 20000 15000 10000 5000 0 0 20 40 60 Concentration (ppm ) 80 100 120 Figure 1. Calibration curve of caffeine The analysis of liquid chromatography allowed determining the mg of caffeine present in the different types of tea. Table 1 shows the caffeine mg for Earl grey, Green, and Oolong teas, which were 13, 6, and 14 mg, respectively. These results indicate that the composition of caffeine may vary with the type of tea. In the case of coffee beans, the concentration or content of caffeine could not be determined because the chromatogram obtained was very noisy and the peak corresponding to caffeine could not be integrated. Table 1. Composition of teas and coffee Concentration Tea of caffeine mg of caffeine (ppm) Earl grey 51 13 Green tea 25 6 Oolong 55 14 Coffee 0 0 As initially mentioned, the caffeine content of tea samples may vary from brand to brand. With respect to that fact, Bigelow brand teas have a low concentration of caffeine as they are below 15mg. Conclusion: The analysis of caffeine in the different tea samples using HPLC revealed that the amount present depends on the type of tea: earl grey (13 mg), green (6 mg), and oolong (14 mg). These levels of caffeine in teas are below of the legal restrictions. References: 1. Belay, A., Ture, K., Redi, M., & Asfaw, A. (2008). Measurement of caffeine in coffee beans with UV/vis spectrometer. Food Chemistry, 108, 310โ€“315. 2. Paradkar, M. M., & Irudayaraj, J. (2002). Rapid determination of caffeine content in soft drinks using FTIRโ€“ATR spectroscopy. Food Chemistry, 78, 261โ€“266. 3. Pura Naik, J. (2001). Improved high-performance liquid chromatography method to determine theobromine and caffeine in cocoa and cocoa products. Journal of Agricultural and Food Chemistry, 49, 3579โ€“3583. 4. Tzanavaras, P. D., & Themelis, D. G. (2007). Development and validation of a highthroughput high-performance liquid chromatographic assay for the determination of caffeine in food samples using a monolithic column. Analytica Chimica Acta, 581, 89โ€“94. 5. Wang, L., Gong, L.-H., Chen, C.-J., Han, H.-B., & Li,H.-H. (2012). Columnchromatographic extraction and separation of polyphenols, caffeine and theanine from green tea. Food Chemistry, 131, 1539โ€“1545. 6. Zou, J., & Li, N. (2006). Simple and environmental friendly procedure for the gas chromatographicโ€“mass spectrometric determination of caffeine. Journal of Chromatography A, 1136, 106โ€“110. Name Time (min) Area (counts*s) Height (counts) 20-1 N/A N/A N/A 20-2 3.641 36.81869 13.97162 #VALUE! 12.12803797 20-3 N/A N/A N/A 50-1 3.660 134.77843 30.92027 #VALUE! 44.39587384 50-2 3.634 194.91547 40.47532 64.2049519 50-3 3.644 201.12346 39.29308 66.24985731 100-1 3.638 307.82968 76.74134 101.3987745 100-2 3.632 299.33679 64.69481 98.60122546 100-3 3.622 280.84091 66.49581 92.50870194 250-1 3.621 854.86829 199.433 281.5927204 250-2 3.619 798.53143 187.32271 263.0354176 250-3 3.616 878.30237 201.45508 289.3118818 500-1 3.61 1791.89771 452.07013 590.249231 500-2 3.68 1988.37024 509.00092 654.9670768 500-3 3.611 2070.66797 485.95731 682.075863 green-1 3.626 336.17807 84.15053 110.7367045 green-2 3.632 566.84943 95.07046 186.7196092 green-3 3.624 317.97144 80.89518 104.7394597 oolong-1 oolong-2 oolong-3 earl-1 earl-2 earl-3 3.614 3.625 3.618 3.627 3.627 3.629 834.54279 821.14508 873.48602 651.40253 654.63177 588.71991 215.25066 205.7533 220.36252 150.84943 153.47398 146.55876 274.8975219 270.4843303 287.7253811 214.5713119 215.6350202 193.9237224 #VALUE! 19.75678778 #VALUE! 43.72329139 57.23475929 55.56299433 108.5172921 91.48270792 94.02944014 282.0113528 264.8866078 284.8707067 639.2568378 719.7607118 687.1755347 118.9943731 134.4358709 114.3910945 304.3785623 290.9486719 311.6070679 213.3109958 217.0222818 207.2437068 ...
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