I normally use isopentane on dry ice to flash freeze fresh tissue, but if I needed to collect whole fresh tissue and flash freeze with just LN (not embedded in OCT), what would I freeze it in? Even cryovials all seem to have this warning:

Cryogenic vials are intended for placement only in the vapor phase of liquid nitrogen, and should not be used for storage in the liquid phase of liquid nitrogen. Immersion of the vials in the liquid phase could result in penetration of the liquefied gas into the vial, resulting in rapid vaporization of the liquid upon removal and possible violent explosion or leakage from the vial/closure perimeter.

The plan is to just store it once frozen then ship it for analysis, but I never use LN. Sorry if this is a dumb question, but would this just mean I would have to skip the immersion in liquid step completely? Like once fresh tissue is in the cryovial, just put it in a dewar right away and leave it to freeze?

Friendly reminder to check your needle alignment next time you pull old samples out of your HPLC