Select septa based on the injection port temperature you will use. Generally, septa with lower thermal limits are softer, and thus are easier to seal or to pierce with a needle. However, softer septa are more prone to damage caused by overtightening the septum nut, and this can reduce the life of the septum. Change all septa regularly, regardless of their thermal limits, to avoid coring and bleed. Use Thermolite Plus septa at inlet temperatures* up to 350 °C, and premium non-stick BTO septa to 400 °C. For tips on preventing septum problems, read our helpful technical article.
*Note: Due to differences in inlet design, the actual septum temperature for a given inlet set point can vary by manufacturer. Restek recommends using only BTO septa in older Thermo TRACE and Focus GCs. For Thermo TRACE 1300/1310, 1600/1610 GCs, this recommendation does not apply; septa can be used to their maximum recommended temperature. For 17 mm inlets, the maximum temperature is 330 °C (for Thermolite Plus the max. temp. is 300 °C).
