5 Replies Latest reply on Nov 16, 2018 11:49 AM by james_jenkins

    GC and Helium shortage




      we are currently unable to get Helium. We'll run our Helium gas inventory in a few weeks. Between other applications for our facility, it is used as a carrier gas on our GCs for solvent analysis (validated method). I'm copying our method below. Would it be best to use N2 or H2? How do I calculate the equivalent flow. Any other option?

      Thanks in advance.


      1.1         Injector

      Mode: splitless

      Temperature: 250 oC

      Carrier gas: Helium

      1.2         Column

      Type: fused silica capillary

      Model:  DB-200 (J&W p/n 122-2033),

      Nominal Length: 30m

      Nominal diameter: 0.25mm

      Nominal film thickness: 0.5 µm

      Mode: constant pressure, 15 psi.

      Nominal initial flow: 1.4 mL/min.

      1.3         Detector

      Type: FID

      Temperature: 300oC

      Hydrogen flow: 40 mL/min

      Air flow: 350 mL/min

      Mode: constant makeup flow

      Makeup gas: Nitrogen (30 mL/min)

      1.4         Temperature profile

      Initial temperature: 40oC for 2 minutes

      Ramp:  increased from 40oC to 130oC at a rate of 20oC/min

      Ramp time: 4.5 minutes

      Post temperature:  maintained at 130oC for 5.5 minutes.

        Total run time:  12 minutes