Analysis of Food Dyes in Beverages Essay

Purpose: To determine the concentration of dye in a sports drink using spectroscopy and graphical analysis. We will be using beers law to find the unknown concentration of dye in a sports drink. Materials: Beakers, 50-mL, 2-3 ; Test tubes (13 x 100)mm 3-8 ; FD&C Blue 1 stock solution, 50-mL ; Lens tissues ; Pipets, serological, 10-mL ; Sample of consumer sports drink, 10-mL ; Spectrophotometer ; Test tube rack Procedure: 1) Preeminently, follow all laboratory safety guidelines ensuring that you have safety goggles on at all times throughout the lab. 2) Fill the cuvette 2/3 of the way with water. 3) Select the appropriate wavelength on the spectrophotometer. 4) Place the cuvette in the spectrophotometer and click the calibrate button. 5) Put 5mL of stock solution into test tube. 6) Fill the cuvette 2/3 of the way with the first solution. 7) Place the cuvette in the spectrophotometer. 8) Wait a few seconds and record the absorption on your data table. 9) Put 4mL of stock solution and 1mL of water in a test tube to make the second solution. 10) Fill the cuvette 2/3 of the way with the second solution. 11) Place the cuvette in the spectrophotometer. 12) Wait a few seconds and record the absorption on your data table. 13) Put 3mL of stock solution and 2mL of water in a test tube to make the third solution. 14) Fill the cuvette 2/3 of the way with the second solution 15) Place the cuvette in the spectrophotometer. 16) Wait a few seconds and record the absorption on your data table. 17) Put 2mL of stock solution and 3mL of water in a test tube to make the fourth solution 18) Fill the cuvette 2/3 of the way with the fourth solution 19) Place the cuvette in the spectrophotometer. 20) Wait a few seconds and record the absorption on your data table. 21) Put 1mL of stock solution and 4mL of water in a test tube to make the fifth solution 22) Fill the cuvette 2/3 of the way with the fifth solution 23) Place the cuvette in the spectrophotometer. 24) Wait a few seconds and record the absorption on your data table. 25) After all data are collected, use them to formulate a graph identifying the linear relationship between absorbency and concentration. —– Data and Calculations: Data recorded: Concentration(Â µM): 5.63 4.344 3.288 2.172 1.086 0 Absorption: .462 .398 .294 .186 .082 0 Water (mL): 0 1 2 3 4 5 Stock Solution (mL): 5 4 3 2 1 0 Linear Regression: y = .088x – .003 A = abc a = Molar absorptivity b = Path length of the sample cell c = Concentration Absorbency of Gatorade = 0.115 0.115 = (130.000)(1)(c) c = 8.85 x 10-7 Conclusion: In this experiment, we prepared solutions and used Beer’s law to analyze the concentration of dye in a beverage. The graph would provide the most accurate means to determine the concentration of an unknown solution and we know that absorbance measurements are most accurate in the range of A values from 0.2 to 1.0.