EXP332

=Researcher= Matthew McBride =Objective= To determine the extinction coefficient of 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= A Mode: [|Spectrum] of Solution A_10000dilution [|Spectrum] of Ethanol [|Spectrum] of difference (Solution A_10000dilution - ethanol) λ max: 321 nm Absorption units at λ max (A): 0.240677 (cannot look at spectrum to obtain this number, but must look at .jdx file directly) Pathlength (L): 1 cm Concentration (c): 2.1298e-6 M Calculated extinction coefficient (ε) of trans-dibenzalacetone in ethanol using Beer's Law (A=εLc): 113004
 * UV/Vis spectrum for Solution A_10000dilution**
 * [USE: spectrumtype=UV-Vis in URL, e.g.**
 * [] -AL]**

E1 Mode: [|Spectrum] of Solution A_10000dilution [|Spectrum] of Ethanol [|Spectrum] of difference (Solution A_10000dilution - ethanol) λ max: Absorption units at λ max (A): Pathlength (L): 1 cm Concentration (c): Calculated extinction coefficient (ε) of trans-dibenzalacetone in ethanol using Beer's Law (A=εLc):

=Discussion= The spectrometer provided a spectrum that "jumped" around a lot and it is believed that the insufficient washes were being completed to obtain a reliable value. =Conclusion= The extinction coefficient (ε) of trans-dibenzalacetone in ethanol was calculated to be 113004, but this extremely high. =Log=

2012-08-06
15:36 Added 0.0499 g of trans-dibenzalacetone (Product 284A from UCEXP284) into a 10 mL volumetric flask. 15:40 Filled the flask with ethanol. All of the crystals dissolved into the solution. The flask was inverted several times to mix. This was Solution A (0.021298 M). 15:44 Added 50 µL (0.0361 g) of Solution A into a 5 mL volumetric flask and filled with ethanol. The solution was inverted several times to mix. This was Solution A_100dilution. 15:50 Added 50 µL (0.0344 g) of Solution A_100dilution into a 5 mL volumetric flask and filled with ethanol. The solution was inverted several times to mix. This was Solution A_10000dilution. 17:00 3 mL of Solution A_10000dilution was added to a cuvette and analyzed by UV/Vis spectroscopy. The sample was analyzed in both E1 and A mode. The sample and the blank (ethanol) were analyzed using the same cuvette.