Hello,
I am trying to change the solvent of my nanoparticles.
They are oleic acid capped iron oxide nanoparticles dispersed in chloroform.
Do you guys know how I can change solvent chloroform to cyclohexane?(or another nonpolar solvent.)
I have two ideas.
1. just evaporate chloform and vacuum and redisperse in cyclohexane.
2. add methanol(as an antisolvent or ethanol) and centrifuge and redisperse in cyclohexane.
3. without adding antisolvent, just centrifuge and redisperse in cyclo hexane.
If you know the best way to change solvent please let me know
and If there are any problems I suggested please point out what is wrong
thank you
I will avoid drying the sample as irreversible aggregation could occur. If cyclohexane an chloroform are miscible, i will try to slowly replace the chloroform by centrifugation and redispersion in a mixture increasing in cyclohexane concentration.
I agree with Omar. The particles might undergo practically irreversible aggregation in the fully dry state. This could make it very difficult to re-disperse them. But I would suggest to try it and check with dynamic light scattering to see whether the dried particles can be re-dispersed or not. It is the most simple way of doing this. So if it works well, then you can go with this. Otherwise, you need to think changing the solvent in the wet state. Centrifuge and re-dispersion is good but it might have the same problem with the "dry" method. If all these do not work, try add cyclohexane into the particle suspension in chloroform. Then try to slowly distill the chloroform away at ~65-70C. Hope this helps.
1. Be prepare that you will lost you sample due to strong aggregation
2. Adding of methanol/ethanol to your system may cause interracial aggregation of your NPs (see work of Reincke, 10.1002/anie.200352339).
3. Looks like plausible, but you will have some CCl4. You can't do solvent exchange for 100%.
4. I would say - a pure liquid-liquid approach. For example, you transfer particles first to water and than from water to cyclohexane.
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