http://nimbus.elte.hu/~lagzi/publikacio/2011/COCIC.pdf

http://pubs.acs.org/doi/abs/10.1021/ja0558241

http://www.sciencedirect.com/science/article/pii/S0021967307012617

Some papers might help you

Please give some more details in the centrifugation procedure that you followed...

You could try other gradients for the centrifugtion. For example, you can pour layers of differernt densities of aqueous glucose (e.g. 0% 20%, 40%, 60%, 80%) and use that for the centrifugation. You just need to be gentle when layering the different densities of solution, and mabye use an old bar tenders trick and pour them on the back of a spoon to prevent mixing of the layers.

http://nimbus.elte.hu/~lagzi/publikacio/2011/COCIC.pdf

http://pubs.acs.org/doi/abs/10.1021/ja0558241

http://www.sciencedirect.com/science/article/pii/S0021967307012617

Some papers might help you

https://www.researchgate.net/post/Separation_of_nanoparticles_according_to_their_shape

Similar topic

Thanks guys. I would try other gradients for centrifugation.

Size exclusion chromatography may work really well for these two very different populations of nanoparticles. The only thing I am not sure about is if this size range is not too large for this method.

The first answer is probably the best solution. Phase transfer to water or buffer (if they're not already there) then separate via gel electrophoresis.

Jf they have a magnetic moment, you can try magnetic separation.

I suggest membrane filtration, use membranes which have different pore size (I did a lot this way and separated different size of nanoparticles)

Yet another possibility might be to introduce tem into a gas stream and use aerodynamic lenses.

Membrane based syringe filtration may help you..

I think membrane syringe filtration is the useful & as well as very quick process to separate different size nano particles.

All the best.

You can try electrophoresis. Smaller particles will be separated from the solvent at lower bias voltages.

Centrifugation is OK, but it is suitable not for all types of NPs.

the best way is to adjust synthesis in such way that more or less the same size nano particles will be formed , as it is reported in attached paper.

Article Polymerization Model for Hydrogen Peroxide Initiated Synthes...

Membrane based ultrafilteration with different pore sizes & Molecular weight cut off may be an appropriate way to get different sized nanoparticles to be separated. I

there are currently more than 6 techniques employed for size dependent separation of nanoparticles.

1. chromatography

2. magnetic feld separation

3. density gradient centrifugation

4. electrophoresis

5.selective precipitatin.

6. membrane filteration.

7. two phase extraction.

more than these there are few more short techniques, all mentioned in a review paper that i mentioned earlier, but giving link here again.

http://nimbus.elte.hu/~lagzi/publikacio/2011/COCIC.pdf

Following thesis may be helpful

http://digitool.library.mcgill.ca/webclient/StreamGate?folder_id=0&dvs=1474249186986~855

What are those nanoparticles?Same mineral?

 Please, How to separate the nano particles from a powder like CaTiO3? I have cube different shapes small and big.

I would suggest using organic solvents for example PEG, the broad molecular weight might help to produce a difference that makes the heavier particles to sink. The point is to try.

Thank you very much I will try

In a powder you have a collection of fused sub and post-micron aggregates. See:

November 3rd, 2015 Adhesion and cohesion  http://tinyurl.com/zwb2wlh

Nov 11th, 2008. Dispersion and nanotechnology http://tinyurl.com/hpywsge 

Have a look on this paper:

https://www.nature.com/articles/srep27494

Regards

 good answer Johanna Marie Galloway

Used Density gradient centrifugation ,but Attention must be paid to the choice of gradient material in order to prevent degradation of the particles being separated.