I am attaching herewith some very good papers for synthesis of monodisperse gold nanoparticles of different sizes. In almost all the papers same procedure is used for the preparation of gold nano seeds. But none of the papers have mentioned the actual amount of HAuCl4 and trisodium citrate used for the preparation of gold nanoseeds.
Can any body please help me by explaining what should be correct volume of HAuCl4 solution (2.5 *exp(-4))M and trisodium citrate (2.5 *exp(-4))M to be used in the procedure?
They use 20 ml aqueous solution containing both: 2.5*10^(-4) M HAuCl4 and 2.5*10^(-4) M trisodium citrate.
You mean 20 mL 2.5*10^(-4) M HAuCl4 and 20 mL 2.5*10^(-4) M trisodium citrate individually? In total its 40 mL?
Then out of 20 mL solution, what should be the individual volume of HAuCl4 and trisodium citrate?
Both of these substances are solids, so I´m not sure what you mean by individual volumes?
The 20 ml solution should contain ~1.5 mg sodium citrate and ~2 mg HAuCl4 (if you´re using trisodium citrate dihydrate and gold(III)chloride trihydrate).
You could also prepare stock solutions of both substances, e.g. with 2.5*10^(-3) M = 2.5 mM. Then you would use 2 ml of each stock solution ( = 4 ml) and add 16 ml water to get your 20 ml aqueous solution containing 2.5*10^(-4) M HAuCl4 and 2.5*10^(-4) M citrate.
Now I understood sir thank you very very much. Really sir you helped me a lot.
Be careful though, sodium citrate is hygroscopic, and depending on how and where you store it, and from environmental humidity, it might contain more or less water molecules in his structure (trihydrate pentahydrate). This will have consequences on how much citrate molecules you weight, and on the overall synthesis.
We do not have means to control humidity in our labs, so we always measure humidity and vary the amount of citrate accordingly (higher humidity, more citrate weighted).
Please check the following reference:
Green and Sustainable Chemistry, 2012, 2, 26-28
http://dx.doi.org/10.4236/gsc.2012.21005 Published Online February 2012 (http://www.SciRP.org/journal/gsc)
Comparative Study on Methods for Preparation of
Gold Nanoparticles
Just before your experiment prepare two stock solutions: 10% solution of HAuCl4*3H2O (1) and 7.5% solution of Na3Cit*2H2O (2). Add 0.02 ml solution 1 and 0.02 ml solution 2 into 20 ml of water.
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