That's an interesting comment ... and a valid question; to which I would reply something along the lines of "that is why vaporizers need to be serviced and calibrated now and then" (generally once a year).
I would have to question the chemist's methods though - he is not testing to "real world conditions"! O-rings are invariably constrained during use (usually mechanically), rather than just being wafted about in vapour(s).
Are we just saying that some O-rings are of poor quality (which is undoubtedly true), or to be aware of using ones made of certain materials? And which anaesthetic agents rendered the most problems (which one seemed to be the most hostile to O-rings)? More information required!
Also, how long was the "time" - hours, days ... years?
