Dear Fiend, I stored at room temperature a couple of hydrogen samples in stopcoks sealled ampoules( as described in Max Coleman paper) over 2 years without apparent change of pressure and D/H ratio. This surpried me because I was aworied that loss due to diffusion trough elastomer gasked is rather significant. So, in your case there is no danger at all to store your samles. Greetings, Stan Halas