Sciencemadness Discussion Board

Sleeve septa

Heavy Walter - 29-2-2016 at 14:44

Hi
I would be glad to know your experience with this kind of septa.
Some comments on the web argue they doesn't seal well in many situations.

Mabus - 5-11-2017 at 09:57

Rubber septa are only for temporary use, like when you're adding an air-sensitive reagent in a reaction flask, and to limit air contamination, it's best to keep the inert gas flowing when using them. They are not very good for storage bottles, exception for air-sensitive reagent bottles (ex: organolithium solutions) which also have an outer main cap.

Sigmatropic - 5-11-2017 at 10:44

I've recently used a septa on a vessel under relatively high vacuum (during freeze-pump-thaw cycles) and could not detect any leakage at ~0.1 mbar. Although preferably I'd use a glass stopper in most cases I sometimes opt for a septum because the risk of introducing the lab atmosphere during sampling is lower.