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 …show more content…
To start off, a wavelength that the FD&C Red #40 dye would be sensitive had to be chosen. Using a random wavelength would likely have rendered all of the results identical because of the dye’s inability to absorb any photon of the wavelength and rather allow all of it to pass through to the detector, concentration notwithstanding. That is why a wavelength that the dye could readily absorb had to be chosen: to set things up in such a way that similar concentrations of dye could provide distinct results and observable trend lines. After looking at a graph of the spectrum of FD&C Red #40, our group concluded that 500 nm would be …show more content…
Since the Low Calorie G2 Thirst Quencher Gatorade in the flavor Fruit Punch was a much darker tint of red than the original stock solution, we diluted it in a 1-to-1 ratio with deionized water to fit it on the produced absorbance curve.
For all of this to be done, we had to learn to set up and calibrate the spectrophotometer with the cuvette and pure deionized water sample. This was done so the machine would read the cuvette and pure deionized sample as complete transmittance of light, so that the rest of the tests would not risk fluctuations due to light being absorbed by the cuvette and
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 …show more content…
To start off, a wavelength that the FD&C Red #40 dye would be sensitive had to be chosen. Using a random wavelength would likely have rendered all of the results identical because of the dye’s inability to absorb any photon of the wavelength and rather allow all of it to pass through to the detector, concentration notwithstanding. That is why a wavelength that the dye could readily absorb had to be chosen: to set things up in such a way that similar concentrations of dye could provide distinct results and observable trend lines. After looking at a graph of the spectrum of FD&C Red #40, our group concluded that 500 nm would be …show more content…
Since the Low Calorie G2 Thirst Quencher Gatorade in the flavor Fruit Punch was a much darker tint of red than the original stock solution, we diluted it in a 1-to-1 ratio with deionized water to fit it on the produced absorbance curve.
For all of this to be done, we had to learn to set up and calibrate the spectrophotometer with the cuvette and pure deionized water sample. This was done so the machine would read the cuvette and pure deionized sample as complete transmittance of light, so that the rest of the tests would not risk fluctuations due to light being absorbed by the cuvette and