Riboflavin Fluorescence Spectra Essay

2065 Words Apr 27th, 2014 9 Pages
Experiment Three Report
Riboflavin Fluorescence Spectra
Name: Holly

Experimental Section: Include all details on preparation of standard solutions. Also include the vitamin tablet brand name; the listed mass of vitamin B2 per tablet; procedure used for extraction of the tablet and dilutions performed.
The experiment began by determining the best wavelength at which to excite the riboflavin molecule, by examining the graph given in the laboratory manual[1]. Because plastic cells that absorb UV light were being used to hold the solutions, the wavelength had to be >320nm. To ensure that we could clearly see the peak of the riboflavin fluorescence in the stock solution, the peak we chose to measure was the one approximated at
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Results Section:
Section 1. Examine the nature of absorption, excitation and fluorescence spectra. Include values for absorption, excitation and fluorescence spectra maxima. Upload your spectra in this section. Figure 1. Fluorescence vs Wavelength graph of Riboflavin 50ppb Stock Solution
The first part of the experiment involved graphing the fluorescence intensity of a 50ppb
Riboflavin stock solution. The wavelength to begin measuring from was based on two factors, the fact that the plastic UV cells that were being used absorbed light up to 320nm, and that the molecule needed to absorb light very strongly, and needed to be seen clearly on the graph. Thus, reading the graph provided in the lab manual[1], it could be seen that there was a peak at around ~450nm which would easily be able to be seen without interference from the plastic cells. In the sample measured from the stock solution, the peak occurred at a

wavelength of 523.52nm and reached a peak of 115.52.
The excitation spectrum was then measured on the same graph. The wavelength at which the peak occurred on the fluorescence spectrum was entered into the program, and a scan range from 350nm to 800nm was used. The excitation spectrum had two peaks, the first occurring at a wavelength of 366.15nm
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