Mass Transfer of Gases through Membranes

Hi All,

First post to this group so I hope it is the right one.

I want to build a membrane inlet system for a mass spectrometer. The membrane should preferentially transfer olefenic /aromatic hydrocarbons while leaving inert gases (N2, O2) and liquid water behind. Dimethyl silicone is commonly used for such an application.

My questions are:

Any recommnended vendors for thin silicone membranes ? Any other materials recommended (and vendors for said materials) ?

Thanks in advance

Phil