User:Allison K. Alix/Notebook/CHEM-581/2013/03/29

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Objective

-Centrifuge concentration gradient solutions to observe absorbance in each

-Observe pH changes in crystal violet hydrogels with the addition of HCl or NaOH

Procedures

Part 1: Preparing Concentration Gradients for UV-Vis Measurements

1) Centrifuge 6 solutions containing varying amounts of R6G prepared on 03/27/2013 for 5 minutes at 11200rpm 3 times.

2) Make the following stock solutions to compare the supernatant absorbances to:

  • 10μL R6G in 1.5mL phosphate buffer
  • 15μL R6G in 1.5mL phosphate buffer
  • 20μL R6G in 1.5mL phosphate buffer
  • 25μL R6G in 1.5mL phosphate buffer
  • 30μL R6G in 1.5mL phosphate buffer
  • 35μL R6G in 1.5mL phosphate buffer

3) Take UV-Vis spectra of stock solutions and supernatants

Part 2: Observing pH changes

1) Separate crystal violet containing hydrogels into two epi-test tubes

2) Add 1mL of 1M HCl to one vial and 1mL NaOH to the other

3) Centrifuge for 2 min at 11200rpm to concentrate hydrogels at the bottom

4) Take UV-Vis of supernatants

Part 3: Prepare hydrogels with indicators

1) Measure out 3 0.5mg samples of PVOh hydrogels containing no lecithin and no dye

2) Dissolve each in 1.5mL phosphate buffer.

3) Allow time for them to separate

4) Add

Data

  • Add data and results here...




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