Riboflavin Synthesis Lab Report

Based on the data from the riboflavin spectrum scan, the maximum absorbance wavelength for this compound is 446 nm. This was the point between 390 nm and 500 nm at which the absorbance value (0.72) was the highest. A blank tube that has the components of the solution being examined except for the compound of interest is then used in combination to provide an even more accurate reading. Then, by using Beer’s Law, the molar extinction coefficient for riboflavin was able to be calculated: 14,400 L/(moles*cm). This is also supported by the experimentally derived extinction coefficient from the standard curve equation (specifically the slope): 13,236.36. The slope of the standard curve is directly correlated with the extinction coefficient and in this experiment, is the same number, for the diameter of the cuvette being used was 1 cm. If this diameter was increased, then the slope of the standard curve would react by decreasing. These values are close, however, not the same. This could be due to a slightly less than perfect R2 value or pipette delivery variation when creating the dilution solutions.
This is the point at which the spectrophotometer is the most sensitive to Riboflavin and can optimally detect its presence in the solution. This, in turn, provides the most accurate absorbance reading of the specific compound of interest. By using this value and the standard curve generated, the concentration of an unknown solution was able to be derived. Based on the results from this experiment it can be deduced that solution #36’s riboflavin concentration is approximately 0.000056 M. This value was quantitatively obtained by diluting the original solution by a factor of 5 and 10. Both dilution factors were tested in duplicate, producing results that are more likely to be