Essay on Uv Visible Spectroscopy Lab Experiment

2190 Words Dec 7th, 2016 9 Pages
UV-Visible Spectroscopy Lab
Purpose
The goal of this lab was to determine the concentration of FD&C Red #40 dye within a bottle of Low Calorie G2 Thirst Quencher Gatorade in the flavor Fruit Punch through the use of UV-Visible Spectrometry: the passing of a beam of a monochromatic light through a mixture in a cuvette to determine the percent transmittance of the light detected. By using a spectrophotometer the relationship between concentration and percent transmittance of FD&C Red #40 can be determined and compared to that of the Gatorade.
Procedure
Once the target dye (FD&C Red #40) and its peak absorbance wavelength (500 nm) are decided, prepare to make several dilutions of the stock solution and tune the spectrophotometer to the same wavelength by following instructions provided to the right

Spectrophotometer should look like this
Prepare eight 10 mL samples using test tubes in the following ratios: mL of Stock Solution (dye and water) mL of deionized water
10 mL
0 mL
8 mL
2 mL
6 mL
4 mL
4 mL
6 mL
3 mL
7 mL
2 mL
8 mL
1 mL
9 mL
0 mL
10 mL

Fill the cuvette with the control solution (plain deionized water) and place it in the spectrophotometer. Make certain to handle the cuvette with KimWipes to minimize the contamination from fingerprints. Calibrate the spectrophotometer to this test for 100% transmittance. Use this as a baseline to compare to for all other tests.
Remove the cuvette, dump the solution, and rinse the cuvette with a small sample of the next solution…

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