Author Topic: Pls help me analysis the problem of the seed-mediated method  (Read 2817 times)

makuna

  • Guest
Dear All,

Currently, I am doing some synthesis work in order to get control-size Au nanoparticles.  I found the fantastic paper: <Seeding Growth for Size Control of 5-40 nm Diameter Gold Nanoparticles> published in Langmuir in 2001 written by Nikhil R. Jana, Latha Gearhear and Murphy.
I followed procedure of this paper to synthesis some Au nanoparticle.

Gold Seed Solution: aqueous solution (25mM HAuCl4 and 25mM trisodium citrate) + ice-cold, freshly prepared 0.1 M NaBH4

Growth Solution: 200ml aqueous solution of 25mM HAuCl4 + 6 CTAB

Formulation: 7.5 of growth solution + 0.05ml 0.1M ascorbic acid + 2.5ml Seed Solution

After stirring 10 min the solution become wine red.

However some problem occurred at the Thiol Capping and Subsequent Solvent Extraction part. In this paper, it writes several steps below:
          --> 10 ul of dodecanethiol was added to 10 ml of particle solution and stirred for 1h
          --> 20 mg of KI and 0.5 ml of toluene were added to the particles solution and shaken for 1-2 min.
results--> The upper toluene portion was red due to particle ext extraction and the water phase was colorless.

I follow the procedure like below:
          --> 10 ul of dodecanethiol was added to 10 ml of particle solution and stirred for 2h
          --> 20 mg of KI  was added into the solution
          --> 0.5 ml of toluene was then added to the particles solution and shaken for 1-2 min
results--> the solution became turbid after shaken 2 min. even after storage 24 hours, the upper toluene was still clear, and the down solution were still red. and there are a few white matter between water solution and toluene.

I just join this field two weeks, and i am lack of experience in this field.  nobody in my group research this. so pls kindly help
me.


So many thanks for your opinion.
__________________________________
Best Regards and Wishes
Makuna

Offline kephra

  • The older I get, the better I was
  • Administrator
  • Participant
  • *****
  • Posts: 7666
  • Likes: 117
  • Illegitimi Non Carborundum
Re: Pls help me analysis the problem of the seed-mediated method
« Reply #1 on: July 25, 2012, 03:16:42 PM »
As I am unable to access the paper you referenced, I cannot comment too much on the procedure.  I suggest that if you haven't already done so, reread the paper to make sure you didn't miss any steps, and repeat the procedure in entirety.  Its also possible that something has been left out of the paper, or something has been obfuscated.

There are other papers which may help you, a google search of "gold nanoparticle toluene" found several lke:
Size-Dependent Phase Transfer of Gold Nanoparticles from Water into Toluene by Tetraoctylammonium Cations:  A Wholly Electrostatic Interaction by Wenlong Cheng and Erkang Wang

I wish I could help you more, but I can not.

This forum's theme is the making and usage of gold and silver nanoparticles using rather simple methods that can be done with food based chemistry, so we (probably meaning I) do not experiment with reagents generally unavailable to the private individual. 

Good luck with your project.
Colloidal Silver is only a bargain if you make it yourself.

kscmac

  • Guest

makuna

  • Guest
Re: Pls help me analysis the problem of the seed-mediated method
« Reply #3 on: July 26, 2012, 07:05:35 AM »
So many thanks for you to read this and your recommend paper. I will try it.

As I am unable to access the paper you referenced, I cannot comment too much on the procedure.  I suggest that if you haven't already done so, reread the paper to make sure you didn't miss any steps, and repeat the procedure in entirety.  Its also possible that something has been left out of the paper, or something has been obfuscated.

There are other papers which may help you, a google search of "gold nanoparticle toluene" found several lke:
Size-Dependent Phase Transfer of Gold Nanoparticles from Water into Toluene by Tetraoctylammonium Cations:  A Wholly Electrostatic Interaction by Wenlong Cheng and Erkang Wang

I wish I could help you more, but I can not.

This forum's theme is the making and usage of gold and silver nanoparticles using rather simple methods that can be done with food based chemistry, so we (probably meaning I) do not experiment with reagents generally unavailable to the private individual. 

Good luck with your project.