All of our non-slit septa are self-sealing and lined with Polypropylene, PTFE or other fluoropolymer for inertness.

HPLC and GC solvents do not present a compatibility issue but acetonitrile and ethers are very volatile and may evaporate after a single use or piercing of the septa. You may need to replace the cap after an injection if you need extreme control over evaporation from the vial.

Click HERE for screw cap ordering information  and pictures