Hemant,

What material are we talking about, iron oxide? One can employ small angle X-ray scattering (SAXS) and dynamic light scattering to monitor cluster formation. See the following article for more details:

"Stable cluster formation in aqueous suspensions of iron oxyhydroxide nanoparticles"

by Benjamin Gilbert, Guoping Lu , Christopher S. Kim

Journal of Colloid and Interface Science 313 (2007) 152–159

Hi Ravi,

For metallic NPs exhibiting plasmon resonance you may use VIS-NIR spectroscopy. High concentrations result in the reduced interparticle spacing that is manifested in spectral broadening of the plasmon resonance and its red-shifting. The effects are more prominent during cluster formation and aggregation of Au NPs. See for example, S. K. Ghosh and T. Pal, “Interparticle coupling effect on the surface plasmon resonance of gold nanoparticles: From theory to applications,” Chem. Rev. 107(11), 4797–4862 (2007).

So, you can identify a presence of agglomeration but not sure that quantification would be easy. Hope it helps!

Thanks Serge. Will NIR work in case of magnetic nanoparticle agglomeration or clustering? Or is there any other way of determining it in magnetic nanoparticles?

Hemant,

What material are we talking about, iron oxide? One can employ small angle X-ray scattering (SAXS) and dynamic light scattering to monitor cluster formation. See the following article for more details:

"Stable cluster formation in aqueous suspensions of iron oxyhydroxide nanoparticles"

by Benjamin Gilbert, Guoping Lu , Christopher S. Kim

Journal of Colloid and Interface Science 313 (2007) 152–159

Thanks Serge!!

Hi Hermant,

You can try to follow up by kinetic of sedimentation of your nanoparticles solution with DLS and zeta potential (charge in the surface), changing the pH, temperature, concentration and time of sedimentation...

Have a look in this two paper:

ACS NANO, Vol. 6 (3), 2012, 2542–2549

Ultrasonics Sonochemistry, Vol. 18 (1), 2011, 382-388

Best

X-ray Scattering andDynamic light scattering are the best methods

Though zeta potential measurements and agarose gel would serve as pretty good indicators of agglomeration too, I agree that DLS would be the best method.

If you have so many methods to opt, always DLS would be the best one.

what do you mean by strength? if the question is how strong you agglomeration is, then DLS and UV-VIS is not going to help you. If you have magnetic NPs, you have to study the magnetic dynamic of NPs which is directly influenced by how strong two adjacent magnetic moment are coupled. Techniques such as complex ac susceptibility, relaxometry and particle spectroscopy would help.