Reduce impact of septum “sweat” by using septum purge..

Have you ever wondered what that “oily” stuff is, that you sometimes see on your septum when you remove it from the injection port? That’s septum “sweat” and consists of cyclic siloxane degradation products.This is occurring at the INSIDE of your injector. When you can "see" it, we are not talking about "nanograms"..

If you have a split/splitless injection port you have in most cases the option to set a septum purge flow. This will help you to prevent these septum bleed products from entering in your system and will give you reduced chance on ghost peaks, lower background and reduced contamination, especially relevant with trace analysis. In MS it will help you significantly reducing siloxane background fragmentation.

You can always keep the septum flush active: also during split and splitless injection.. If you have the option and understand its function: better USE it.. It’s a good investment for spending 2-3 mL/min of your carrier gas.