Centrifuge question

Aaronse_r

Hey, I've been reading on this site for a week of so now, and just wanted to say thanks for all your contributions. Very helpfull!

My question is, im making zinc ferrite nano-particles and i was wondering at what RPM i should set the centrifuge to, so that the zinc ferrite comes out of solution. Is there anyway of calculating this or is it simply trial and error? I have tried putting it next to a magnet instead of centrifuge, but it is slow. Thanks!

chemisttree

These particles would be colloidal in nature and would not be easy to isolate by centrifugation either. It can be done and is called ultracentrifugation. I think the 'ultra' in ultracentrifugation means to 'turn the knob to its fastest setting and wait awhile'.

staf9

Magnetic centrifuge maybe? I'm sure someone's invented it.

Moonbear

More accurately, you should ask how many times g you need to set the centrifuge for, and then calculate the appropriate RPM for the rotor in your model (if you still have the instruction manual, often you don't even have to break out a pencil and calculator, just look for the conversion table ).

Ultracentrifugation does NOT mean just set the centrifuge on its highest setting. It means use an ultracentrifuge that reaches MUCH higher g forces than a standard laboratory centrifuge (50,000 or 75,000 x g upward to about 1,000,000 x g).

If you need an ultracentrifuge and only have a standard laboratory centrifuge, you're unlikely to get any reasonable separation.

Can you run your sample through a filter (with centrifugation if necessary) to do a size separation? I don't know what else is in your solution to have a clue if this is feasible (and still might not have a clue if I did know).