带预切口隔垫的瓶盖

Pre-cut septa: The silicone material is cut through in Y-form while the PTFE layer remains uncut. The silicone layer represents 95% of the total septa thickness while the PTFE layer is only 5% or less.
The Y-form shape of the cut was chosen for several reasons. Since the PTFE layer is uncut, this product provides protection against contamination until the needle pierces through it. The needle can easily penetrate through the Y-slit of the septa material (only the thickness of the PTFE layer needs to be penetrated by the needle). Less pressure is required for the autosampler needle to penetrate the pre-cut septa, resulting in fewer bent and/or broken needles.
The uncut PTFE layer provides a better seal than other commercially solid slitted septa until the needle punctures the septa. The Y-shaped cut allows air to ener the vial eliminating vacuum formation. The design provides the needle with a larger target area for penetration even when the needle doesn′t come down in the center of the septa.