User:Moira M. Esson/Notebook/CHEM-581/2013/04/05

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Objectives

  1. Finish decanting all microsphere samples.
  2. Rinse all microsphere samples with hexanes.
  3. Perform unmodified pipette pressure testing on microspheres that underwent diffusion testing on 2013/04/03


Microsphere Work-Up

Decanting: The general protocol described on 2013/03/01 was followed.

  • The organic safflower oil layer needed to be removed several times. After removing a layer of safflower oil, the microspheres were allowed to sit for 15 minutes, and more oil was then able to be removed.
  • Due to the presence of what appeared to be small particles in the safflower oil, the safflower oil layer that was removed from the samples was saved, labeled and parafilmed. The safflower oil layer will be vacuum filtered and obtained solids will be tested using DSC in order to see if there is a difference between the larger spheres that formed at the bottom of the vial and the smaller particles suspended in the safflower oil layer.


Rinsing with hexanes:

  • Although the previous method for microsphere work-up included the vacuum filtration of the microspheres with a hexane rinse described on 2013/03/08, this step was unnecessary. The prepared microspheres were incredibly small in size, making a rinse in hexanes sufficient enough for the removal of all mineral oil. Similarly, due to the small size of the spheres difficulties arose in finding filter paper with a small enough pore size to ensure the retention of the spheres.


General Protocol:

  1. After the removal of the safflower oil organic layer from the sample container, ~3mL of hexanes were added to each vial.
  2. The samples were stirred and allowed to sit for ~3minutes.
  3. Using a pasteur pipette, the hexanes were removed from the vial and discarded in the appropriate waste container.
  4. Repeat 1-3 twice.
  5. The samples remained in the fume hood over night without a cap to ensure complete removal of all hexanes.


Pressure Testing

  • Pressure testing using an unmodified pipette was completed.
  • The general protocol for fluorescence was followed.
  • The specific parameters included:
    # Excitation Slit Width: 10
    # Emission Slit Width: 10
    # Scan Speed: 1200
  • The general protocol for unmodified pressure testing described on [[

Table 1. Samples that were used for unmodified pressure testing

Sample Order PVOH vs. Clay Ratio PVOH Type Clay Selection Amount of Hydrogel Used (g)
150:50146K110% CEC Laponite w/ DMHXLBR0.1883
290:10146KNaMT0.1742
390:10146K110% CEC Laponite w/ DMHXLBR0.1404
490:10146K50% CEC NaMT w/ Bu3HdP+0.1721
550:50146K50% CEC NaMT w/ Bu3HdP+0.1884
650:50146KNaMT0.1349


Notes

  • On 04/05/13, the DSC instrument lost contact or communication with the computer, indicated by the warning that only 2 data points were obtained. As such, microsphere samples originally prepared on 04/03/13 were incorrectly run and analyzed.
  • Therefore, all microsphere samples placed in the DSC on 04/03/13 were re-run over the weekend -- no results could be collected.


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