Hello all,
I have synthesized the AuNPs using 1.2 mM auric chloride salt.
How can I know its concentration in suspension form?
Hi Vijay
There are several approaches for determining Au nanoparticle concentrations. The first requires determination of the mean size and shape of your particles by dynamic light scattering and TEM. Once you have this information about your Au nanoparticles, you can calculate the number of Au atoms per particle from the particle volume using the density of Au (19.3 g/cm3) and Avagadro's number. At the start of your Au NP synthesis, you added a precise amount of Au3+, thus you know exactly how many Au atoms were used in the synthesis. Thus
N (total number of Au particles) = total Au atoms/Au atoms per particle
Divide the total number of Au particles by the final volume (in mL) of your synthesis solution and your will get the Au nanoparticle concentration (particles/mL).
UV-vis absorption spectra of your Au nanoparticles can also be used to determine the Au nanoparticle concentration. The attached papers provide detailed information about this.
Best
Geoff
Hi Vijay, just to add to the excellent suggestion above, you could use functional thiols to label the Au particles for chromogenic or fluorescence quantification:
http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=103941322
Can you just pipette 1 mL suspension and quickly weight the mass, then remove the solvent by evaporation or even heating. Then measure the mass left, You can easily get the w/w concentration of your particles. With known density of the particle and solvent, you can convert it to mL/g or other units, etc.
Thank you so much Geoffrey I.N. Waterhouse sir, for you nice information.
It was really needed to me.
Thanks a lot.
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