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Riboflavin

Scott Prahl

Riboflavin This page summarizes the optical absorption and emission data of Riboflavin that is available in the PhotochemCAD package, version 2.1a (Du 1998, Dixon 2005). I reworked their data to produce these interactive graphs and to provide direct links to text files containing the raw and manipulated data. Although I have tried to be careful, I may have introduced some errors; the cautious user is advised to compare these results with the original sources.

The JavaScript libraries that I used to graph the data do not work with IE7 and earlier — you will not see the cool interactive graphs. Chrome seems to work best. You can resize any of the graphs by clicking and dragging a rectangle. If you hover the mouse over the graph, you will see a pop-up showing the coordinates. One of the icons in the upper right corner will let you export the graph in other formats.

Absorption

This optical absorption measurement of Riboflavin were made by R.-C. A. Fuh on 06-24-1997 using a Cary 3. The absorption values were collected using a spectral bandwidth of 1.0 nm, a signal averaging time of 0.133 sec, a data interval of 0.25 nm, and a scan rate of 112.5 nm/min.

These measurements were scaled to make the molar extinction coefficient match the value of 33,000cm-1/M at 266.5nm (Koziol, 1966).

Original Data | Extinction Data

Fluorescence

The fluorescence emission spectrum of Riboflavin dissolved in ethanol. The excitation wavelength was 450nm. The quantum yield of this molecule is 0.3 (Koziol, 1966; Sun, 1972). This spectrum was collected by on 06-24-1997 using a Spex FluoroMax. The excitation and emission monochromators were set at 1 mm, giving a spectral bandwidth of 4.25 nm. The data interval was 0.5 nm and the integration time was 2.0 sec.

Samples were prepared in 1cm pathlength quartz cells with absorbance less than 0.1 at the excitation and all emission wavelengths to uniformly illuminate across the sample, and to avoid the inner-filter effect. The dark counts were subtracted and the spectra were corrected for wavelength-dependent instrument sensitivity.

Original Data | Emission Data

Notes

The fluorescence yield is 0.36 in acetone and 0.37 in dioxane (Koziol, 1965).

References

Dixon, J. M., M. Taniguchi and J. S. Lindsey (2005), "PhotochemCAD 2. A Refined Program with Accompanying Spectral Databases for Photochemical Calculations, Photochem. Photobiol., 81, 212-213.

Du, H., R.-C. A. Fuh, J. Li, L. A. Corkan and J. S. Lindsey (1998) PhotochemCAD: A computer-aided design and research tool in photochemistry. Photochem. Photobiol. 68, 141-142.

Koziol, J. and E. Knobloch (1965) The solvent effect on the fluorescence and light absorption of riboflavin and lumiflavin. Biochim. Biophys. Acta 102, 289-300.

Koziol, J. (1966) Studies on flavins in organic solvents I. Spectral characteristics of riboflavin, riboflavin tetrabutyrate and lumichrome. Photochem. Photobiol. 5, 41-54.

Sun, M., T. A. Moore and P.-S. Song (1972) Molecular luminescence studies of flavins. I. The excited states of flavins. J. Am. Chem. Soc. 94, 1730-1740.


© 5 March 2012 Scott Prahl