Iron is a ferro magnetic material , which will be attracted to magnet . Other forms of iron may be ferrimagnetic , and which may not be attracted towards magnet. chances for the iron nano particle to get converted into its oxide. Being ,iron nano particle has high surface area, the reactivity of it is very high . make sure that the solution does not contain dissolved oxyge.

Moreover, you used plant extract, the biomolecules would have been adsorbed over the surface of the the particle . Wash thoroughly the iron particles using using suitbale solvent.

dry the nano particle in the absence of air. Then you test for magnetic behaviour. Check magenetic moment with EPR spectroscopy.

Dr.G.Sekaran

What colour are your particles? Some iron oxides and oxyhyroxides are not attracted to magnets (e.g. green rusts). If they are red or orange, it is likely that they are ferric (Fe3+) species, green might be ferrous (Fe2+) or mixed valence. Magnetite (Fe3O4) and maghemite (Fe2O3) are usually black in colour, and would be attracted to a magnet. If you have not excluded oxygen from your system, it is likely that you have formed ferric oxides, rather than iron or a ferrous or mixed valence species. Even if the particles are small, they should still be magentically seperable if they are a magnetic mineral. It might be a good idea to do some TEM to image your material so you can look at the morphology of the particles, and electron diffraction could provide a crystal structure that would allow confirmation of the mineralogy of the particles.

Thank you

Dear Marslin Gregory

My plant extract contains rich amount of Isoflavonoids and phenolic compounds

i think u need to contact Armats lab in guindy, chennai. in there two ppl named Gouthm and Praveen are working with magnetic nanoparticles in green synthesizing. hope they can help you in particle isolation thing.All the best.

before helping further:

- what is your iron source?

- which pH do you precipitate?

- which color has your solution? etc

- there is already some similar examples, see iron oxides / humic acids.

enjoy!

Iron Source - Ferric chloride

pH - 4.0

Color of solution - Black

Which plant's extract you used?

Fabaceae family plants