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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).
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.
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.