Concentration of synthesized nanoparticles

[knopik]

Hi!
I am dealing with the synthesis of inorganic metallic nanoparticles and at the moment looking for the methods how to define the concentration of final nanoparticles in the colloidal solution.

 

[chemisttree]

Stephen Africk has a http://www.azonano.com/Details.asp?ArticleID=1904"

If you don't want to go there, you could filter them and count them using an electron microscope. The techniques in that example are similar to those used to count cell cultures with a microscope. You should find methods in the biological literature.

 

[knopik]

many thanks, but to do it I should contact either Mr.Stephen Africk or to buy this device. What I need is to calculate the concentration of produced nanoparticles using common simple methods, applying Uv-vis spectroscopy or some chemical calculations

 

[staf9]

Not 100% sure on this, but I believe it involves measuring the dilectric relaxation time of hydrogen protons in an aqueous solution of your nanomaterial. To do this would require a magnetic resonance spectrometer. Once you have the relaxation time, the inverse of this is proportional to the concentration of your nanomaterial.

Definitely should look it up, I haven't dealt with stuff like this too much.

Now here's something that I'm even less sure about: I read a paper last year that used changes in pressure differential across a filter to determine the concentration of nanoparticles in air, but now I'm just derailing the thread...

If you could get your hands on a DMA you could sort out the particles, perhaps that would help.

 

[Andy Resnick]

How to *define* or how to *measure*? What accuracy do you need? What precision?

Can you simply measure the density of the solution? Absorbance?

 

[knopik]

How to *define* or how to *measure*? What accuracy do you need? What precision?

Can you simply measure the density of the solution? Absorbance?

you are right. Actually I need the definition of the concentration. How to define it correctly using the Uv-vis absorbance or calculating the density (volume) taking into account the initial concentration of precursors?

 

[knopik]

Not 100% sure on this, but I believe it involves measuring the dilectric relaxation time of hydrogen protons in an aqueous solution of your nanomaterial. To do this would require a magnetic resonance spectrometer. Once you have the relaxation time, the inverse of this is proportional to the concentration of your nanomaterial.

Definitely should look it up, I haven't dealt with stuff like this too much.

Now here's something that I'm even less sure about: I read a paper last year that used changes in pressure differential across a filter to determine the concentration of nanoparticles in air, but now I'm just derailing the thread...

If you could get your hands on a DMA you could sort out the particles, perhaps that would help.

Thanks I will think it over

 

[ashishdubey]

Hii..
Do you got any solution to calculate the concentration of synthesized nanoparticles. If yes then please reply me back...or reply me on ashishdubey.85@gmail.com

I will be thankful to you for your kind suggestion..


Ashish

 

[TheDude_]

According to Sigma-Aldrich (http://www.sigmaaldrich.com/materials-science/nanomaterials/silver-nanoparticles.html):
"The concentration of silver nanoparticle solutions is calculated using the Beer-Lambert law, which correlates the optical density (OD, a measure of the amount of light transmitted through a solution) with concentration."

This may not be helpful to your specific application, but for TiO₂ nanoparticles, there is a report in the literature for using the beer-lambert law to determine molecular concentration by spectraphotmetric measurements. They report using 215 nm light with a molar absorptivity of 6050 M^-1cm^-1, where the extinction coefficient at that wavelength is independent of particle size.

Gao, R.; Safrany, A.; Rabani, J. Radiat. Phys. Chem. 2002, 65, 599.

 

[ben11]

Hi,

isnt it possible to take like 1 ml of solution lophylize it and weight it? (make sure you know the wieght of the ependorf before hand)