Cryo-vials

The cryo-vials is manufactured for stability in extremely cold storage conditions

Hi Tammy,

Thanks for the question and the information. Without knowing how your lab is set-up and you analytical method, I can give some general advice below.

Looking at the research Cotinine is pretty stable in plasma and most studies seem to use -20°C storage for up to a year but there is no reason why you couldn't use -80°C, most labs tend to have much more -20°C space available so -80°C space is at a premium.

I would suggest for the samples to use labelled eppendorfs (especially if a small sample size) for the plasma storage and these can happily be stored at -80°C for long periods.

Alternatively, if your lab works in a 96-well format (or if you have a large number of samples) you could also use labelled polypropylene tubes in 96 well plates. These also store well under -80°C conditions for long periods of time. The positive aspect of using these is that you can cap the tubes and the 96 well plate usually comes with a lid, which means that samples can take up much less space in your freezer. These also hold ca 1 mL of fluid and depending on the amount of sample you could also create back-up samples. Usually in bioanalysis we try not to exceed 3 freeze-thaws unless we have validated for more, this means that if you exceeded 3 freeze-thaws on your primary sample you can use the backup to complete analysis.

I hope this helps and just to summarise; if you have a small number of samples and plenty of freezer space - go for the eppendorfs. If you have a large number of samples, feel free to use the eppendorfs but I would suggest in future moving to 96-well format.

I have also included a couple of papers below which have some information of Cotinine storage stability from their analysis.

Article Temporal Stability of Urinary and Plasma Biomarkers of Tobac...

Article Total Cotinine in Plasma: A Stable Biomarker for Exposure to...

Good luck with your analysis!