Split vent vs Septurn purge vent


Our lab is looking at directing potential airborne contaminants coming from a GC towards an exhaust vent. The three possible locations I could locate are the split vent, septum purge vent and vacuum pump. Between the split vent and septum purge vent, which one theoretically has the potential to release more harmful substances into the air? What is the difference between the both? Why do some instruments have a back and front septum purge vent while others only have a front (I think this is because the back is using a VI inlet?) Would it cause issues if tubing is placed on top of the events as seen in the picture?

  • The split vent typically runs at a higher flow than the septum purge flow.  Septum purge flow is often 3 mL/min, while split flow is often 20 or more. I thought all of our inlets had septum purge vents, but I haven't worked with a VI in a long time.  Connecting tubing to these vents shouldn't be a problem as long as the vent lines do not cause any restriction of the flow.

    There is a trap with charcoal filter that can be mounted on the split vent.  PN RDT-1020 includes the housing and three filters; PN RDT-1023 is the three filters by themselves.

  • Hi Chemist 23,

  • You can understand about flow in above documents..In VI inlet there is no septum purge as they are used for headspace or purge & trap connection mostly..

    Lance already explained you about flow and filter to connect at exhaust line..

    Since your purpose is to check airborne contamination then you have to check exchaust line as well as oven also becuause after completion of Run, oven flap open to throw heat to become cool..So i will suggest to keep instrument under fumehood or put instrument near to portable fumehood..

    Even from detector air contamination may possible..

    Like this nothing will go in air of Lab using fumehood..

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