Abstract: The purpose of this lab was to determine the food dyes present in a selected beverage, their concentration, and then replicate the solution within a 20% margin of error. The beverage we chose was Gatorade Frost Riptide Rush. A spectrometer was used to determine which food dyes were present in the sampled beverage, red 40 and blue 1 were determined to be present. The next step was to determine the concentration of the dyes, this was done by testing the absorbance of the red 40 and blue 1 dyes at varying concentrations; 100%, 80%, 60%, 40%, and 20%. The results for each dye were then plotted in a graph and a trendline was added. The slopes of the trendlines (y=mx) for red 40 and blue 1 were then used to determine the concentrations, which were found to be 15.34% (0.0000138 mol/L) and 14.12% (0.0000028 mol/L) respectively. To replicate the color of the original beverage a 100mL solution was designed, containing 15.34mL red 40, 14.12mL blue 1, and 70.54mL deionized (DI) water.
Introduction: This lab was divided into three sections; identifying which dyes are present, determining the concentration of those dyes, and finally to recreate the solution within a 20% margin of error. To identify the dyes present a sample of the beverage was tested in a spectrometer, the highest absorption rates were found to be at 503.7 nm (A=0.281) and 630.7 nm (A=0.270). This lead to the conclusion that the beverage contained red 40 and blue 1. To determine the concentration of the dyes a series of dilutions was prepared for both dyes and tested with the spectrometer. This data was converted into point graphs and a trendline was established. The slope of the trendline (y=mx) was then multiplied by the Absorbance of the associated dye to find the concentration. The final goal was to replicate the beverage using the data gathered. To accomplish this a solution was designed consisting of 15.34% red 40 and 14.12% blue 1.
Experimental Procedure: To complete the experiment a variety of materials and equipment was required. The spectrometer tests required a computer with Logger Pro software, samples of Gatorade Frost Riptide Rush as well as red 40 and blue 1 dyes, DI water, a spectrometer, cuvettes. In order to prepare the dilutions and replicated solution 10mL & 100mL graduated cylinders, various beakers, a 200mL erlenmeyer flask, and a glass stirring rod.
To identify the dyes present in the Gatorade, a test was performed with the spectrometer. The first step was to set-up the spectrometer and calibrate it using a sample of pure DI water. Following this a cuvette was partially filled with a sample of Gatorade and inserted into the spectrometer to be tested. The points of highest absorption were determined to indicate the presence of red and blue dyes.
The initial step to determine the concentration of the dyes previously found was to prepare a set of serial dilutions at 20%/40%/60%/80%/100% dye concentration. To prepare the 20% dilution 1mL of red 40/blue 1 was combined with 4mL of DI water. This method was used to produce the remaining dilutions with 2mL/3mL, 3mL/2mL, 4mL/1mL, and 5mL/0mL (mL dye / mL DI water). Each of the previous dilutions was tested in the spectrometer and data was recorded. Using the data obtained two Beer Law plots were plotted for both dyes and trendlines were added. The slope of the trendline was found and used to calculate the actual (mol/L) and percent concentrations of red 40 and blue 1 in the selected Gatorade.
In order to replicate the color of the Gatorade, a 100mL solution consisting of red 40, blue 1, and DI water. This was accomplished by combining 15.34mL red 40, 14.12mL blue 1, and 70.54mL DI water in a 200mL erlenmeyer flask. A sample of this solution was then transferred into a cuvette to be tested in the spectrometer. The solution was tested alongside the data from the Gatorade sample, and the margin of error was calculated to conclude how similar the two solutions were.