Septa must withstand high chemical and mechanical loads during everyday use in analytics. Especially the application in combination with GC systems requires a high thermal load capacity of the material. A selection of the most common GC septa can be found below.
|Material||Max. operating temperature||Features|
|BTO||400 °C (300 °C for 17 mm septa)||
Optimized for GC/MS systems
|TR-Green||350 °C||Long lifetime|
High mechanical resistance
Up to 400 injections per septa lifetime
|TR-Blue||200 – 250 °C||
Easy to penetrate
Suitable for routine applications
The Inlet septa is an essential part of the sample introduction into a GC system. The purpose of the septa is to create a barrier which is penetrated readily from the nozzle needle and is maintained while the internal pressure is held up without contaminating the analysis.
Septa are available in a number of different materials and sizes (according to the specifications of the system). They are generally made from compositions made of silicone rubber with low bleed and high temperature limit. Therefore Septa are recommended in high/upper temperature limits. Materials for lower temperatures are generally softer, seal better and resist a greater number of injections as higher temperature material. If septa are used above the recommended temperature limit, it may leak into the inlet or decompose. This can lead to sample loss since the hermetic seal is lost, that results in lower column flow and a reduction in the life of the column.
To avoid greater damage and contamination in the entire GC system, the septa should be changed regularly. Thus leaks can be prevented or sample loss reduced in the system. By replacing the septa at reasonable intervals of decomposition of the septa in the system aperture can be counteracted and thus extend the life of the column.
If you can't find a suitable product for your applications, do not hesitate to contact us. Our expert team will advise you independently.