I am working with Iodine in our lab and we typically use Teflon, but for an experiment we might need all the valves in such a material. Yet, a few places that I have found that carry such products are not on hand and would be available in weeks. I would like something by Monday/Tuesday. However,some places that carry a lot of Teflon products have PVDF valves and fittings available. Cole Parmer and few other places say PVDF is resistant to Iodine, but I am not sure how much compared to Teflon. Any suggestions?