Objectives
- Perform error analysis on the compiled data calibration curve.
- Determine the standard deviation for the data points.
- Determine the confidence interval for 90% and 95% confidence.
- Determine if any data can be ruled out using a Q-test.
- Determine the molar extinction coefficient for both adenosine and inosine.
- Determine the concentration of an unknown adenosine sample(taken from Javier's group).
- Perform Grubb's test on outlying peak of adenosine molar extinction coefficent graph.
- Perform data analysis on molar extinction coefficient graphs(both adenosine and inosine).
Group calibration curve data
Figure 1. CHEM-571 Calibration Curve for Adenosine
- The Grubb's test will be employed to determine whether the points that lie outside of the line of best fit are outliers
Figure 2. CHEM-571 Calibration Curve for Inosine
Table 1. Molar absorptivity for Adenosine at 259nm and Inosine at
| Molar Absorptivity(Lmol-1cm-1)
|
'
|
| Adenosine |
14025
|
| Inosine |
11007
|
Matt Hartings What wavelength does this molar absorptivity correspond to?
Table 2. Standard deviation of Inosine Absorbance values
| Comcentration(M)
|
Standard Deviation
|
| 4.80E-05 |
0.10707708
|
| 4.00E-05 |
0.12254917
|
| 3.20E-05 |
0.0943149
|
| 2.40E-05 |
0.06671357
|
| 1.60E-05 |
0.04841797
|
| 8.00E-06 |
0.04748368
|
Table 3. Standard deviation of Adenosine Absorbance values
| Concentration(M)
|
Standard Deviation
|
| 3.00E-05 |
0.072537576
|
| 2.50E-05 |
0.045680412
|
| 2.00E-05 |
0.064123319
|
| 1.50E-05 |
0.056753854
|
| 1.00E-05 |
0.0313289
|
| 5.00E-06 |
0.046559639
|
Table 4. 95% Confidence Intervals for Adenosine Absorbance values
| Concentration(M)
|
Confidence Interval
|
| 3.00E-05 |
0.063580821
|
| 2.50E-05 |
0.04003991
|
| 2.00E-05 |
0.056205534
|
| 1.50E-05 |
0.049746033
|
| 1.00E-05 |
0.027460487
|
| 5.00E-06 |
0.040810573
|
Table 5. 90% Confidence Intervals for Adenosine Absorbance Values
| Concentration(M)
|
Confidence Interval
|
| 3.00E-05 |
0.053358707
|
| 2.50E-05 |
0.033602552
|
| 2.00E-05 |
0.047169171
|
| 1.50E-05 |
0.041748187
|
| 1.00E-05 |
0.023045567
|
| 5.00E-06 |
0.034249313
|
Table 6. 95% Confidence Intervals for Inosine Absorbance Values
| Concentration(M)
|
Confidence Interval
|
| 4.80E-05 |
0.093855474
|
| 4.00E-05 |
0.10741711
|
| 3.20E-05 |
0.082669136
|
| 2.40E-05 |
0.058475948
|
| 1.60E-05 |
0.042439442
|
| 8.00E-06 |
0.041620516
|
Table 7. 90% Confidence Intervals for Inosine Absorbance Values
| Concentration(M)
|
Confidence Interval
|
| 4.80E-05 |
0.078765997
|
| 4.00E-05 |
0.09014728
|
| 3.20E-05 |
0.069378126
|
| 2.40E-05 |
0.049074562
|
| 1.60E-05 |
0.035616303
|
| 8.00E-06 |
0.034929038
|
Table 8. Q-test at 90% confidence for Inosine Absorbance Values
| Comcentration(M)
|
Qexp values
|
Suspected outlier(Abs)
|
| 4.80E-05 |
0.435606061 |
0.331
|
| 4.00E-05 |
0.605769231 |
0.189
|
| 3.20E-05 |
0.880658436 |
0.171
|
| 2.40E-05 |
0.987804878 |
0.128
|
| 1.60E-05 |
0.475806452 |
0.089
|
| 8.00E-06 |
0.534883721 |
0.004
|
- Note: With 5 data points Qc=0.64. As such, data points 0.171 and 0.128 can be discarded with 90% confidence
Table 9. Q-test at 90% confidence for Adenosine Absorbance Values
| Concentration(M)
|
Suspected Outliers(Abs)
|
Qexp
|
| 3.00E-05 |
0.558 |
0.794444444
|
| 2.50E-05 |
0.442 |
0.705357143
|
| 2.00E-05 |
0.406 |
0.8625
|
| 1.50E-05 |
0.304 |
0.675496689
|
| 1.00E-05 |
0.195 |
0.5
|
| 5.00E-06 |
0.136 |
0.405405405
|
- Note: With 5 data points Qc=0.64. As such, data points 0.558, 0.442, 0.406, and 0.304 can be discarded with 90% certainty.
Table 10. Grubb's Test for Adenosine Absorbance Values
| Concentration(M)
|
Suspected Outliers(Abs)
|
Gexp
|
| 3.00E-05 |
0.558 |
1.753573888
|
| 2.50E-05 |
0.442 |
1.725028241
|
| 2.00E-05 |
0.406 |
1.75599146
|
| 1.50E-05 |
0.304 |
1.481520326
|
| 1.00E-05 |
0.195 |
1.532131655
|
| 5.00E-06 |
0.136 |
1.426127891
|
- Note: With 5 data points at a 95% confidence level Gc=1.67. As such, absorbance values 0.558, 0.442 and 0.406 can be discarded with 95% confidence.
Unknown Adenosine Solution
Figure 3. Absorption Spectrum of Unknown Concentration
- Using the molar extinction coefficient determined from the calibration curve above the concentration of the unknown is 4.7344E-5 M.
Matt Hartings Based on your calibration curve, what is the error in this measurement?
| 
Project name
