A STUDY OF THE RATE OF METABOLISM OF CAFFEINE IN URINE PRESENTED BY KATIE COLEMAN AND COLLEEN WALSH

OBJECTIVE The objective was to use UV-Vis spectroscopy to test the levels of caffeine, metabolized in one person, before consumption and after consumption of Coca-Cola, Lipton black tea, and a Red Bull energy drink

EXPERIMENTAL CONTROLS One person’s urine samples were used throughout the experiment 8oz of each beverage was consumed Water was the control beverage Red Bull, Coca-Cola, and Lipton Black Tea were the beverages tested No other caffeinated food/beverage was consumed during the experiment 10mL of each urine sample was washed three times with 5mL CH 2 Cl 2

PROCEDURE Established a maximum wavelength of 230nm Created a calibration curve for pure caffeine Stock Solution 500ppm: –0.025g Caffeine –50mL of Methylene chloride (CH 2 Cl 2 ) Dilutions: –100ppm –50ppm –25ppm –12.5ppm

PROCEDURE (CONT.) A 10mL sample was poured into a separatory funnel with a 5mL wash of CH 2 Cl 2 The funnel was shaken briskly for 3 min. to separate the inorganic layer from the organic layer The lower layer was removed The sample was washed three times The sample was then run through UV-Vis This was done for each of the 16 samples

DATA

WATER

WATER RESULTS The control samples were inaccurate due to errors The graph reflects these results

COCA-COLA

COCA-COLA RESULTS 8oz of Coca-Cola contains 80.2ppm (0.802mg/0.01L) of caffeine Level of caffeine in the body decreases with time

LIPTON BLACK TEA

LIPTON BLACK TEA RESULTS 8oz of black tea contains 106ppm (1.06mg/0.01L) of caffeine Level of caffeine seems to increases with time; however, all the values remain under 0.2

RED BULL

RED BULL RESULTS 8oz of Red Bull contains 381.6ppm (3.816mg/0.01L) of caffeine Level of caffeine decreases with time

DISCUSSION

CONCLUSION The caffeine metabolizes 30 min is the threshold interval for all beverages tested, all caffeine levels in the beverages dropped dramatically after consumption After the 30 min interval the caffeine graph levels off Although we had a percent error range from 15-40%, we feel that we were successful in our findings, considering our experimentation is new.

CHALLENGES Possible sources of error –Separatory funnel extraction –Wash control first instead of last –Loss due to evaporation –Experiment ran only once –Only one person’s specimen was used

FUTURE RESEARCH Usage of different instruments –Centrifuge as means of separation Use fresh urine samples –Ours were up to a week old Better calibration curve –Be patient and know your dilutions!!! Test more than one person to see if the results are the same

REFERENCES –Caffeine content of popular drinks –Chromatography experiment labs/caffeine/caffeine_intro.htm chem35lab/Lab7-IsolationOfCaffei.pdf

Thanks Dr. Diab for all your patience and guidance!!!