I'm trying to collect zebrafish blood for RNA analysis. We plan to pool blood from 6-10 animals to get the necessary volume (~500 uL), but my question is about how to prevent coagulation of the blood. Obviously, the pre-coated tubes that are commercially available are too large for my purpose. So I think given the small volume that it would be ideal to have the EDTA (or other anti-coagulant- Sodium citrate, heparin, etc) on the pipette tip that the blood is collected with, the blood can easily be pipetted up and down a few times to ensure good mixing with this method, as well.
But I don't know how to make these myself. We own powdered EDTA (I think the typical used is K2EDTA), and the tips, although we can buy anything needed. Is it just as simple as making a liquid of dissolved EDTA and water then coating the inside and letting dry? If so what concentration of solution? These would be 200 uL non-barrier tips that I am working with.
Thanks in advance!