User:Omar Choudary/Notebook/Omar Choudary CHEM-571 AU-2011/2012/2011/09/07

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Contents

Objective

  • Repeat nanoparticle synthesis experiment from 8/31/2011 using two separate buffers: water and 50mM acetate pH 4.3.
  • Attempt to improve nanoparticle synthesis.

Description

  • Created 10 mL aqueous mixtures of 2.5mM Chloroauric Acid(HAuCl4) and 15 μM Bovine Serum Albumin(BSA) in water.
  • Created the same mixture from the previous step using 50mM acetate pH 4.3 instead of water.
  • Both mixtures placed into oven set at 80 degrees Celsius.
  • Obtained UV-visible spectra (200 - 900nm) every 30 minutes over 2 hours.

Data

  • Calculations
  • Stock Solutions: 2.5 mM HAuCl4 , 15 μM BSA
  • M1V1 = M2V2
  • HAuCl4

M1 = 2.5 mM V1 = 1 mL M2 = 0.25 mM V2 = 10 mL

1 mL of HAuCl4 stock solution for each test tube mixture

  • BSA

M1 = 0.015 mM V1 = 1 mL M2 = 0.0015 mM V2 = 10 mL

1 mL of BSA stock solution for each test tube mixture


  • H2O Buffer


Full absorbance spectrum of mixture in H2O buffer.

Image:OC-9-7-1.jpg


H2O buffer spectrum focused on 550 nm.

Image:OC-9-7-2.jpg


Absorbance of mixture over 2 hours at 550 nm.

Image:OC-9-7-3.jpg


  • Acetate Buffer


Full absorbance spectrum of mixture in acetate buffer.

Image:OC-9-7-4.jpg


Absorbance spectrum focused on 550 nm.

Image:OC-9-7-5.jpg

Absorbance of mixture at 550nm over 2 hours.

Image:OC-9-7-6.jpg

Notes

  • Molar ratio of Au/BSA for H2O buffer mixture was 166.
  • Molar ratio of Au/BSA for acetate buffer mixture was 160.
  • Both mixtures appeared as clear solutions with purple fibers floating in them.
  • For both spectra showing AuNP formation over time at 550 nm, the increasing trendlines indicate gold nanoparticle (AuNP) synthesis. The mixture in acetate, had a greater slope than the water mixture indicating that AuNP density was greater in the acetate mixture.
  • All UV-Vis spectra were taken using a Shimadzu UV-2550.
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