Chromatography Forum

Dear all,


Maybe not the right place to ask, but do you think that it is likely that acetonitrile evaporates in a freezer at -20 degrees Celsius? We stored some calibration samples for over a year and now find an increase in concentration of approximately 20% . Samples were stored in polypropylene screw cap tubes (no inlay in the cap).
Can you share your experiences?

Thanks, Bert

Hi

Well seems like it can happen depending on type of lids and solvent.

Personally I have seen APIs stored in frezzer (~-20°C) lose a few hundred ppms methanol over time (weeks)(snap lid).

Also several collegues has noted that dichloromethane can "wander" from one bottle to another in refridegerators (+2-8°C).

So seen over a full years time I am not completly surprised.

For sure this can happen, even if the solvent is frozen solid, it still has a vapour pressure, and the vapour can still diffuse through the wall or cap of the container, or through any gaps.

Peter