Red 40 And Blue 1: Spectrophotometry

The purpose of this experiment was to quantify the amounts of Red 40 and Blue 1 in six different
Kool-Aid™ samples through the use of spectrophotometry. In order to do so, in Part A, eight standard solutions were prepared through serial dilutions of Red 40 and Blue 1. In Part B the λmax and the absorbance values of the standard solutions were recorded. Finally in Part C, the λmax and the absorbance values of the Kool-Aid™ samples were determined. The values recorded during the experiment were used to plot calibration curves. The calibration curves provided the molar absorptivity, 휺, of the food dyes, which were then used along with Beer’s Law to calculate the concentrations of the food dyes in the drink samples.
To perform serial dilution in Part A, each new diluted solution starts

In this experiment, the
?irst solution began with 5 mL of the stock solution and then equal amount of water was added to dilute it and reach a total volume of 10 mL; this was labeled R1. Then, the next solution began with
5 mL of the R1 solution and then equal amount of water was added; this was labeled R2. This step was repeated until R4. Since the concentration of every new solution is half of the previous solution, this is known as a 2-fold dilution. One of the bene?its of using serial dilutions is that it provides a wide range of concentrations, thus aiding in the accuracy of the calibration curves. Another bene?it is it ensures accurate dilutions to low concentrations even if the process was started from stock solutions of high concentrations. If performed incorrectly, the serial dilution can lead to a gross systematic error, because if one step of serial dilution had an error, especially one if the initial ones, such as R1 and B1, it would impact all the other solutions. This would provide incorrect absorbance values in relation to concentration, thus causing an error in the trendline. This would