G3449-90000 inlet interface

Is there a way to modify or remove the metal tube under the turn top assembly for the G3449-9000 inlet interface?  This tube prevents the use of headspace liners with I.D. > 2mm

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  • Thanks for the corrections and I did mean < 2mm, we have been using a liner that has a 1.5 mm opening so we were wondering if there is any significant difference between the 2mm straight liner and the 1.5 mm straight liner besides the volume (2 mm is 250uL and 1.5 is 140 uL) or could they be considered equivalent?

  • Hello  ,

    Thank you for the clarification.

    Well, I am not a consumables expert, so I will move this post over to the Consumables section. But in terms of volume I would say that is pretty significant. More so if you go from a higher volume to a lower volume as the could result in the gas volume exceeding the liner volume (if all parameters stay the same and only the liner changes). Moving from a lower volume to a higher volume I think should be no problem, but I would still wait for an answer for someone that is more consumables-savy than me,

    A useful tool would be the Vapour Volume calculator, that you can download from the link below (along with other tools). Using that would ensure that you have the proper liner volume at least, for your analysis type.

    GC Calculators and Method Translation Software | Agilent

    Let's see if someone has other suggestions for you.

  • HI tbutter5,

    the below answer is absolutely right, the internal volume plays an important role and overloading a liner results in back-flash into the supply lines. Worst case is the contamination of or to the EPC, where you would need to exchange all tubing (best case) or the EPC (worst case). In case of headspace it is less critical as you already have a gas sample filling the liner, still you shouldn't exceed the internal loner volume.

    What are the dimensions of your current liner? ID, OD, Length?



  • 18740-80200 Inlet liner, direct, 1.5 mm id, for gas samples, headspace, length 78.5, volume 140 uL, we want to switch to 5190-6168, which is 2 mm ID and 250 uL volume,  This is for headspace only, not sure if the sample loop plays a role in what is injected but we have GCs that have 3 mL loops and 1 mL loops

  • Hi Tamara,

    both are for Headspace and both have an OD of 6.5 mm, so yes you can use it. The sample loop determines what volume you will inject and the liner is only kind of an appendage connecting the HS system with the GC, that should normally have the smallest possible volume to not add dead volume to the flow path. I personally would use the 1.5 mm ID liner for the 1 mL sample loop and the 2 mm liner for the 3 mL loop. I wouldn't recommend going bigger as this will give you broader peaks and therefore worse LODs.

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