EXP331

=Researcher= Matthew McBride =Objective= To determine the extinction coefficient for trans-dibenzalacetone in ethanol =Procedure= Dissolve a known amount of trans-dibenzalacetone in ethanol and calculate the extinction coefficient using UV/Vis Spectroscopy and Beer's law. =Results= UV/Vis Spectrums: For Solution A_10000dilution [|Spectrum] of Solution A_10000dilution in E1 mode [|Spectrum] of Ethanol in E1 mode [|Spectrum] of difference (Solution A_10000dilution - ethanol) λ max: 328 nm Absorption units at λ max (A): 0.141815 (cannot look at spectrum to obtain this number, but must look at .jdx file directly) Pathlength (L): 1 cm Concentration (c): 2.0886e-6 M Calculated extinction coefficient (ε) of trans-dibenzalacetone in ethanol using Beer's Law (A=εLc): 67899 =Discussion= The volumetric flasks were not washed throughly enough to provide an accurate measurement from the dilutions. =Conclusion= Calculated extinction coefficient (ε) of trans-dibenzalacetone in ethanol was 67899, but this number is higher than some of the 33000 number that has been reported in literature. =Log=

2012-08-06
9:36 0.0607 g of trans-dibenzalacetone (Product 284A from UCEXP284) was added to a 5-dram vial. 9:46 A new bottle of ethanol was opened and 9.7907 g (density of 0.7893 g/mL, so 12.4043 mL) was added to the 5-dram vial. All of the crystals were observed to dissolve. This was Solution A (0.020886 M). 9:55 1 mL of Solution A was added to a 10 mL volumetric flask and the flask was filled with ethanol. The solution was inverted several times to mix. This was Solution A_10dilution. 10:05 1 mL of Solution A_10dilution was added to a 10 mL volumetric flask and the flask was filled with ethanol. The solution was inverted several times to mix. This was Solution A_100dilution. 10:12 1 mL of Solution A_100dilution was added to a 10 mL volumetric flask and the flask was filled with ethanol. The solution was inverted several times to mix. This was Solution A_1000dilution. 10:21 1 mL of Solution A_1000dilution was added to a 10 mL volumetric flask and the flask was filled with ethanol. The solution was inverted several times to mix. This was Solution A_10000dilution. 12:37 3 mL of Solution A_10000dilution was added to a 1 cm pathlength cuvette and analyzed by UV/Vis spectroscopy. The sample was analyzed in E1 mode and both the blank (ethanol) and the sample were analyzed using the same cuvette.