User:Helen L. Slucher/Notebook/CHEM 571/2013/09/03

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Overview

  • Determine the molar absorptivities of adenosine and inosine.
  • The data that we generate today will be important when we study adenosine deaminase (ADA), which converts adenosine to inosine. The difference between these two molecules is that adenosine contains a primary amine whereas inosine contains a carboxyl group.
  • Adenosine and inosine have different absorption spectra. We will be observing changes in UV-Vis spectra to determine changes in concentration of both adenosine and inosine. In order to do this, we will need to know the molar absorptivity (ε) of both of these molecules.

Description

  1. Determine molar absorptivity of both adenosine and inosine by plotting graphs of A (at one specific wavelength; I suggest you use a peak value from the spectrum) vs c.
  2. Pool data from all of the groups to develop a full calibration curve.
  3. Determine standard deviations from the group's data, a confidence interval, and perform a Q-test to remove any outlying data.

Directions

Stock Solutions

Adenosine has a molecular weight of 267.24g/mol; inosine has a molecular weight of 268.2g/mol.

Adenosine solution concentrations (M) Inosine solution concentrations (M)
3.00x10-5 4.80x10-5
2.50x10-5 4.00x10-5
2.00x10-5 3.20x10-5
1.50x10-5 2.40x10-5
1.00x10-5 1.60x10-5
0.50x10-5 0.80x10-5
RANDOM RANDOM

RANDOM adenosine 0.25 x 10-5
RANDOM inosine 0.4 x 10-5

Absorption Spectra Spectrum of each of your samples along with a blank

Unknown Determine the concentration of these unknowns from the calibration curves by propagating the error from the calibration curve to your concentration calculation. After making your calculation, find out what the calculation of the samples should be.

Calculations

Calculations:
0.11 g of Adenosine . \tfrac{1 mole}{267.24 g}=4.1x10-4 moles of Adenosine.
\tfrac{4.1}{0.1 L of water}10-3 moles of Adenosine=4.1x10-3 M of Adenosine.


0.1 g of Inosine . \tfrac{1 mole}{268.29 g}=3.7x10-4 moles of Inosine.
\tfrac{3.7}{0.1 L of water}10-4 moles of Inosine=3.7x10-3 M of Inosine.

To dilute the solution of adenosine and inosine to the concentrations listed above:

 C_1\times V_1 = C_2\times V_2

Adenosine

C2 (M) V2 (L) C1 (M) V1 (L)
3.00x10-5 1.00x10-3 4.1x10-3 0.000007317073171
2.50x10-5 1.00x10-3 4.1x10-3 0.000006097560976
2.00x10-5 1.00x10-3 4.1x10-3 0.00000487804878
1.50x10-5 1.00x10-3 4.1x10-3 0.000003658536585
1.00x10-5 1.00x10-3 4.1x10-3 0.00000243902439
0.50x10-5 1.00x10-3 4.1x10-3 0.000001219512195
0.25x10-5 1.00x10-3 4.1x10-3 0.000000609756098

Inosine

C2 (M) V2 (L) C1 (M) V1 (L)
4.80x10-5 1.00x10-3 3.7x10-3 0.000012972972973
4.00x10-5 1.00x10-3 3.7x10-3 0.000010810810811
3.20x10-5 1.00x10-3 3.7x10-3 0.000008648648649
2.40x10-5 1.00x10-3 3.7x10-3 0.000006486486486
1.60x10-5 1.00x10-3 3.7x10-3 0.000004324324324
0.80x10-5 1.00x10-3 3.7x10-3 0.000002162162162
0.40x10-5 1.00x10-3 3.7x10-3 0.000001081081081

Data

  • Image:Screen shot 2013-10-12 at 1.19.38 PM.png
  1. Series 1: 0.25
  2. Series 2: 0.5
  3. Series 3: 1
  4. Series 4: 1.5
  5. Series 5: 2
  6. Series 6: 2.5
  7. Series 7: 3
  • Image:Screen shot 2013-10-12 at 1.20.31 PM.png

Notes

Only data for adenosine was collected; inosine data will be collected tomorrow.


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