Thank you for your kind reply, maybe the age/quality is indeed the issue because I have the impression that the washing steps are going even worse than before…

I think I’ll just have to bite the bullet now and order pre-made paramagnetic beads which I can then use with the different protocols your team has developed. If that all…Read more

After a long hiatus, I tried the protocol again, paying attention to the different critical points. I filtered my iron salts solution to have a perfectly clear solution to start with, degassed the solutions using sonification and also adjusted the pH of the water.

But again, I’m having the same problem: after a few washes the solution…Read more

Thank you for taking the time to exhaustively answer my questions.

I will try the protocol again when I have some free time in the lab (might take some time though) and I’ll report back here.

Thank you again!

Kind regards, Jonas

Thank you for your fast reply! And don’t get me wrong, I’m very happy that you and your team have made this protocol available to the research community. It would be a really great way to stretch our budget.

1) If the ratio would be wrong would I still get a magnetic precipitate before washing? Or does the faulty ratio cause MNPs…Read more

I’m also having some problems with the washing steps. Right after synthesis, the MNPs are quickly attracted to the magnet rendering the supernatant completely clear. Subsequent washing steps however, give rise to an increasingly dark colored solution.

I have tried degassing the water with N2 (with a homemade contraption) and also…Read more