Guanidine thiocyanate is a common component of DNA purification solutions (for example TRIzol) as its chaotropic properties inactivate DNAzes. When you say "fix" what do you mean by it? To stop it from being degraded or to preserve its interactions with RNA and DNA binding proteins?

Mateo Glumac For the one grant, my colleague mentioned that it is possible to use this substance for the fixation of natural material (e.g. phytoplankton sample) so that DNA degradation does not occur and subsequently it can be isolated from the material for further characterization (PCR, etc.).

Unfortunately, I did not find any methodology anywhere on how to use such a fixative solution - concentrations, buffers, etc.

I would appreciate any advice.

Thanks a lot.