PTFE Silicone Septum for 9mm Autosampler Vial Caps

PTFE/Silicone Septa: High quality, pure silicone is laminated to PTFE to give a pure, highly inert septum with excellent resealing characteristics even after repeated punctures. PTFE/Silicone septa are the preferred product for use in most HPLC and GC applications where resealability and high purity are critical. Works well for applications where ease of needle penetration is important. Septa-silica gel has strong repetitive sealability, and it can maintain good close performance after multiple injections; PTFE is a material with better chemical conditions at present, and it can withstand strong acids and alkalis. The two materials After compounding, the bottle can be used for various laboratory purposes such as sealed sampling, chemical storage and so on. PTFE/Silicone/PTFE Septa: A layer of PTFE is laminated to each side of high purity, medium durometer silicone to form a septum that is the most resistant to coring while maintaining good resealing characteristics. The PTFE/Silicone/PTFE septum is recommended for the most critical applications such as ultra trace analysis or where there is a longer time between injections or for internal standard methods. PTFE/Silicone/PTFE septa provide superior performance with any autosampler employing a large diameter, blunt tip needle.

Septa Material	Advantages	Chemical Resistance	Applications	Max Temp
PTFE/silicone	Excellent resealing capabilities	Excellent until punctured Not suitable for chlorosilanes	Multiple injections than moderate resistance	200°C
Pre-slit PTFE/silicone	Reduces coring Prevents vacuum from inside the vial	Excellent until punctured than moderate resistance	Multiple injections	200°C
PTFE/silicone/ PTFE	Resistant to coring Autoclavable	Excellent	Above average resealing Multiple injections or applications with long periods between injections	200°C

Pre-slit or Not Chromatography septas can be pre-slit or not and must be considered by evaluating a few factors. A pre-slit septum is an ideal choice in applications requiring 20% or more of the sample injection each time from the vial so that suction is avoided. The slit allows ambient gas to equalize the gas in the vial so that a vacuum is not created in the vial from the tight seal around the needle. If coring or clogging from a narrow needle or needle deflection from highly durable septa material is a concern, then choosing a pre-slit septum is a better choice. The non-pre-slit septas help to reduce carryover from vial to vial because the resealing characteristics of the septum act as a squeegee to wipe solution from the outside of the needle. Typically, a non-slit septum exhibits resealing capabilities for a limited number of needle punctures but for long-term storage in the vial, using a new non-punctured septum is best practice. A PTFE/Silicone with slitted septum allows for easier needle penetration as well as to release the vacuum that forms when a large volume of sample is withdrawn from a vial. This septum provides chromatographic characteristics similar to that of a septum without a slit except that the ability to withstand exposure to aggressive solvents is slightly lessened. Pre-slit septa are highly recommended improving injection to injection reproducibility with autosamplers withdrawing greater than 50µL of sample from a 2mL vial, due to possible cavitation (vacuum).

Part No.	Description
S91	White PTFE/Red Silicone Septa, Φ9*1mm
S92	Red PTFE/White Silicone Septa, Φ9*1mm
S93	Red PTFE/White Silicone/Red PTFE Septa, Φ9*1mm
S944	I Pre-slit Blue PTFE/White Silicone Septa, Φ9*1mm
SX944	X Pre-slit Blue PTFE/White Silicone Septa, Φ9*1mm