User:Helen L. Slucher/Notebook/CHEM-572/2014/02/04

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  • To synthesize citrate-coated GNPs 40-45nm in size
  • To synthesize polydopamine-coated GNPs

Citrate Coated GNPs

  1. Prepare stock solutions
    1. Dissolve HAuCl4 in water to have a solution of 10mM
    2. Dissolve 250mg of the citrate sodium salt into 25mL of water
  2. In a beaker mix 50mL of water and a volume of the gold stock solution corresponding to 1.214*10^-2 moles of Gold
  3. Bring solution to a boil
  4. Add a 0.5mL of the citrate sodium solution and reflux for 30 minutes
    1. Note color change from dark blue to red


  • We made three separate citrate-GNP solutions at the same time
  • One of the solutions changed color to blue first, however, it also did not turn red (deep purple)
  • The other two solutions changed color to blue and then red
  1. Solution 1: 20-25nm
  2. Solution 2: 14-16nm
  3. Solution 3 (deep purple): 4-5nm
  • We made two more citrate-GNP solutions and this time we used a stir bar
  • The solutions changed color to blue and then red
  1. Solution 4: 35nm
  2. Solution 5: 25nm