Storage Condition
Frozen
Last updated
Stored below freezing, conventionally around minus 20 degrees Celsius for lyophilised material and sometimes minus 80 for long-term research storage. The purpose is to slow chemical degradation over months to years. In almost every case the requirement applies to the powder, because freezing an aqueous solution introduces problems of its own.
Why it matters here
Frozen and Refrigerated are different classes, not degrees of the same instruction, and a record specifying one is not satisfied by the other. Knowing which physical state the value applies to matters before any reconstitution arithmetic is relevant.
What it is not
Colder is not automatically better: ice crystals and freeze-concentration can damage peptides in solution, every freeze-thaw cycle is a separate stress, and a frost-free freezer deliberately warms above freezing on a cycle, so it does not hold a stable minus 20.
Also called
- frozen
- -20c
- freezer
The alias -20c is the specification itself. Domestic freezers are generally built to reach about minus 18, which is close to but not the same number.
Compounds carrying this term
None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.