Hi Gülşah,

I've not worked with retinoic acid, but we've got a similar problem with vitamin D which is also sensitive to light and air.

You can keep your aliquots safer by aliquoting in standard Eppendorfs, and then wrapping the tubes in tinfoil to block the light.

Air should be displaced from the tubes before storage. You can buy argon gas for this from some scientific suppliers, however it's very expensive. Argon gas is also sold as "wine preservation gas" and this is a lot cheaper.

All the best!

Sam

Hi Sam Siljee,

I do not know how to achieve this condition in standard Eppendorf tubes without a special and expensive apparatus. I thought that even if there was no argon, I could find nitrogen gas at least, and I would withdraw the air from the vials with an injector and replace it with nitrogen. Unfortunately, I do not have this kind of tubes and special caps. How can the same be done in Eppendorf tubes?

Thank you very much for the answer.

Hi Gülşah Torkay,

There's no need for special equipment or special tubes. Argon is heavier than air and will displace the air simply by being wafted into the top of an open Eppendorf before closing it. The wine saver will likely come as a pressurised aerosol can with a nozzle.

Of course there may be other suggestions, but I believe this will be one of the easiest and cheapest options.