Question

3. Preparation of standard addition solutions. Prepare six 25 mL volumetric flasks as follows: Volume of tablet solution (mL) 2.00 2.00 2.00 2.00 2.00 2.00 Volume of standard riboflavin solution (mL) 0 1.00 2.50 7.50 12.50 20.00 Top each flask to the mark Measure the volume of standard riboflavin solution using a burette. using 1% acetic acid and mix thoroughly. 3. Obtaining the fluorescence spectra. Prior to obtaining the fluorescence spectra, you will need to determine the maximum excitation wavelength of quinine as well as the optimal region for obtaining the maximum emission intensity. See the instructor for details on using the instrument. Writeup This is a standard additions experiment, so be sure to use the correct formulae. Recall that, in a standard additions experiment like this, your calibration line will have volume of spike added as the x-axis (instead of concentration). The % error of your concentration (determined using the regression line) will be the same as the % error in your mass of riboflavin. 1. Report the mass of riboflavin in your tablet. 2. Compare your results to the reported package amount. Bear in mind that riboflavin slowly decomposes when exposed to light. 3. Explain why the wavelength of maximum excitation is different from the wavelength of fluorescence. For more information, see: S. Pandey, T.L. Borders, C.E. Hernández, L.E. Roy, G.D. Reddy, G.L. Martinez, A. Jackson, G. Brown, and W.E. Acree Jr. J. Chem. Educ. 1999, 76, 85.
Tablet Information(75 Tablets -each tablet contains 5.1mg riboflavin ), concentration of riboflavin in unknown powder solution: 1.01±0.04ppm. Find the Report the mass of riboflavin in your tablet.

Answer 1