I think the dry ice could work fine because is between negative 70 and 80 celsius. But for storage for a long period of time the liquid nitrogen still the better option.

Dear Thao,

I recommend to consult this article by Lu et al., true experts in metabolomics:

Article Metabolite Measurement: Pitfalls to Avoid and Practices to Follow

Best regards,

Simon

Dear Thao

I would use LN2 as the first choice, but if it is impossible on any reasons, I would use chilled methanol and proceed to extraction right after.

Just to put samples on dry ice, in my mind, can be problematic, as it will take more time to freeze the sample compared to LN2, and can cause inconsistency.

If still it is only one option, I would make a fine powder of dry ice to ensure the full contact of dry ice with dish bottom.

Dear Albert Batushansky ,

Many thanks for your suggestion. It is very useful. Could you please help me with another question? Is it fine if i mince tissue samples of mussels and then put inside vials with 60% cold methanol and then keep in dry ice before storing at -80 at the lab?

Best regards.

Thao

Thanks Simon Lagies ,

Its the paper that im looking for.

Best regards.

Thao

Thanks Dielson Da Silva Vieira !!!

Dear Thao V. Nguyen

I personally would avoid to damage/pulverize/grind fresh tissue. I would recommend to deep-freeze it first. However, sometimes there is no way to avoid it, for example, when only specific part of the organ (left ventricle let say) is needed. So if You will do it fast and consistent, may be effect will be neglected.

But why are You using 60% and not 100% MetOH?

In respect to storing at -80C under methanol, I think it can be Ok for a week (at least I noted that my extracts almost did not degrade in methanol for a week), but make sure the samples are tightly closed and protected from evaporation and contamination.

Dear Albert Batushansky,

Many thanks for your details. I really appreciate your time. Im thinking of 60% because I see many authors used that for bacterial culture. I will make some trials with methanol and see. I could not take liquid nitrogen with me when I do field sampling, so i am thinking for dry ice or cold methanol.

Many thanks and wish you a nice day.

Thao

Hi everyone,

I have a question regarding quenching mammalian cells with liquid nitrogen. Do we need to worry about having liquid nitrogen touching the cells? Should we parafilm the plate to avoid this, or we can add liquid nitrogen directly on top of the cells?