Caps, Screw Top, with Red PTFE / White Silicone Rubber / Red PTFE Septa, fitted in "knurled", polypropylene, Blue Caps. For use with 9-425mm thread, 12x32mm autosampler vials. MICROSOLV Brand. 100/PK
Additional Info:
The 9502S‑20C‑B screw caps feature a specialty, multi‑layer septa construction developed to address the performance needs of specific legacy autosampler systems, particularly older instrument designs such as the Agilent® 1050.
This septa configuration incorporates red PTFE layers on both the needle‑contact and sample‑facing sides, with a white silicone rubber core. The outer red PTFE surfaces provide additional needle wiping action during injection, helping remove residue from the needle exterior as it penetrates the septa. This makes the caps particularly useful in methods where carryover reduction is desirable and mechanical cleaning is limited by instrument design.
Compared to standard silicone rubber / PTFE septa, this construction also offers a small but meaningful improvement in resealing performance after injection, supporting better vial integrity during repeated or extended autosampler runs on older platforms.
The knurled polypropylene caps allow secure handling and consistent sealing, while the fitted septa design ensures reliable performance without the need for bonded‑septa construction in instruments where extreme injection forces are not present.
These caps are intended for specialized or legacy HPLC applications and are not generally required for modern autosamplers designed around pre‑slit or low‑force septa technologies.