User:Puja Mody/Notebook/Chem 571: Gold Nanoparticles/2012/09/05: Difference between revisions

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==Conclusions==
==Conclusions==
* For the redone AuNP/BSA UV-Vis tests done. Instead of just one peak at 550nm, there was an uncharacteristic peak at around 490-500nm as well. As a result, distilled water was also tested to see if it had been a factor in causing an adjustment to the same. In the data spreadsheet, the  UV-Vis data for each of the samples then had the UV-Vis data for water subtracted from it in order to test if it was the water that had caused the peak. The graphs clearly show that without the water, the background, the second peak was removed.
* Other observations were that compared to the original 14 solution data, the absorbency was much higher as compared to the retested 6 samples where the absorbency is smalled by an entire order of magnitude.
* The tris buffer solutions were placed in a UV-Vis a total of three times. for the data on those tests look at next entry.
* The tris buffer solutions were placed in a UV-Vis a total of three times. for the data on those tests look at next entry.

Revision as of 10:47, 12 September 2012

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Day 3

Goals

  • Remake certain AuNP/BSA solutions at specific concentrations to retest using UV-Vis to check/clarify discrepancies
  • Centrifuge the gold solutions in order to separate the fibers and then combine the fibers with the Tris buffer at various concentrations in order to test how long it takes to (if it does) re-suspend in the solution.

Procedure

  • The AuNP stock solution from yesterday was combined with a new stock solution of BSA. The concentrations that were retested were: 120, 128, 130, 132, 133, 134. These samples were then placed in the oven for four hours in order to allow for the BSA to unfold and to be wrapped around the AuNP.
  • The AuNP solutions that has been used previously were meanwhile transferred from glass test tubes to plastic ones in order to prepare them for centrifuging. The centrifuging was necessary in order to separate out the fibers as best as possible from the solution.
  • The AuNP fibers were centrifuged for five minutes at a speed of 3000 rpm at a temperature of 10°C. After which, the BSA solution was pipetted out as best as was possible. 7 test tubes which had centrifuged out the most of the AuNP fibers were used for the next step.
  • A serial dilation was used inorder to place various concentrations of the tris buffer and water into the test tubes. The concentrations ranged from .1M to 1×10−2 to 1×10-7.
  • After centrifuging, the AuNP fibers were separated from solution by pipetting out as much of the aqueous solution as possible prior to adding the tris buffer.
  • After these new solutions were made, they were placed in UV-Vis two times. each time to test if the fibers had been dissolved into the tris buffer solution.

Calculation

  • Retested concentrations:
    1. Solutions were made with the mole ratios of

(HAuCl4/BSA) 120, 128, 130, 132, 133, and 134. Volume of HAuCl4 stock solution was calculated for each tube and inserted. The water needed for each tube was calculated by subtracting the volume of HAuCl4 stock solution and BSA stock solution from 6mL.

      1. m1v1=m2v2
      2. 15μM*(volume BSA stock

solution) = (1.5*6)

        1. 0.6mL BSA stock

solution in each tube

      1. 7520μM*x mL=6mL*(1.5*120μM)
        1. 0.143mL HAuCl4

stock solution

        1. 5.257mL H2O
      2. 7520μM*x mL=6mL*(1.5*128μM)
        1. 0.153mL HAuCl4

stock solution

        1. 5.247mL H2O
      2. 7520μM*x mL=6mL*(1.5*130μM)
        1. .155mL HAuCl4

stock solution

        1. 5.245mL H2O
      2. 7520μM*x mL=6mL*(1.5*132μM)
        1. 0.157mL HAuCl4

stock solution

        1. 5.243mL H2O
      2. 7520μM*x mL=6mL*(1.5*133μM)
        1. 0.159mL HAuCl4

stock solution

        1. 5.241mL H2O
      2. 7520μM*x mL=6mL*(1.5*134μM)
        1. 0.160mL HAuCl4

stock solution

        1. 5.240mL H2O

Data

Test Tube Tris Buffer (mL) Water (mL) Concentration of solution M
1 10 0 .1 M
1 1 9 1 x 10^-2 M
1 1 9 1 x 10^-3 M
1 1 9 1 x 10^-4 M
1 1 9 1 x10^-5 M
1 1 9 1 x 10 ^-6 M
1 1 9 1 x 10^-7 M


Links to spreadsheet and chart of redone UV-Vis:


New concentrations of remixed AuNP/ BSA samples for UV-Vis

Concentration mL of AuNP mL of BSA mL of H2O
120 0.144 0.6 5.256
128 0.156 0.6 5.247
130 0.155 0.6 5.245
132 0.158 0.6 5.242
133 0.159 0.6 5.241
134 0.16 0.6 5.24

Conclusions

  • The tris buffer solutions were placed in a UV-Vis a total of three times. for the data on those tests look at next entry.
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