Hello,
I see by the lack of responses that our subscribers seem to have little experience with regard to your question. I am among that group, but in order to potentially stir the pot, I would ask if there might be any chance that the concentration might be due to aggregation? I have experienced aggregation around -60C in metal containers that had minute imperfections in the surface of the vessels. I would guess that polycarbonate does not display these types of imperfections, but perhaps you could confirm this.
