Weekly Bonus for the week of February 23 - March 2, 2010:
This assignment is due at the start of class on Tuesday, March 2. As usual, failure to completely answer the questions will result in no points awarded. And remember: There is no partial credit awarded for Bonus Questions. Ever. Don't bother asking.
Enjoy!
You have been asked to build a standard curve for a spectrophotometric assay for the presence of total protein in an aqueous sample. You need to make five (5) dilutions of a 2.0 mg/mL protein standard such that the final concentrations are: 0.0 mg/mL, 0.2 mg/mL, 0.4 mg/mL, 0.6 mg/mL, 0.8 mg/mL and 1.0 mg/mL. The final volume of each of these dilutions is 20 microliters.
After preparing the standard dilutions and adding reagent to the sample, you collect the following data:
|
Standard Protein
Concentration (mg/mL)
|
Absorbance at
595 nm
|
|
0
|
-0.00008
|
|
0.2
|
0.2773
|
|
0.4
|
0.5372
|
|
0.6
|
0.7283
|
|
0.8
|
0.9083
|
|
1.0
|
1.0444
|
For the bonus questions this week, you are to answer the following:
- Give the volume of protein standard (2.0 mg/mL) and the volume of water necessary to construct the dilutions necessary to produce the standard curve given in the table.
- If you have an unknown protein sample that gives an absorbance reading of 0.882, what is the concentration of the protein?
Successful completion of this exercise will result in 5 points being awarded to you. |
