Wide bore guard column to narrow bore true column

[ZeroAir]

I am thinking about switching to a .53 guard column (larger surface area = better deposition/longer protective lifetime of/from non-volatiles), but I am using a .32 true column. I will join them with one of Agilent's deactivated glass junctions.

I sometimes have trouble sealing leaks at the junction when using .32 guard/.32 true column, and I think this problem will be exacerbated when increasing the local pressure at the junction by incorporating a .53/.32 union.

Do any of you use wider guards than your actual column and if so do you experience leaks?

Thanks,

Luke

[Peter Apps]

I have gas flow switches with three different diameters of fused silica connected with Siltek Y connectors (Restek). Once they are put together properly they do not leak.

Peter

[ZeroAir]

Cool, thanks! I guess I will order the parts and give it a shot then.

Cheers,

Luke

[AICMM]

zeroAir,

I have use a 0.53 to 0.25 in the past with the idea that I take more out of the inlet but still do 0.25 chromatography. Having said that, I used a glass press fit but I glued it. I also, always, recommend you do all of this with nothing hooked up so you are not fighting gas pressure while trying to make the seal.

Best regards,

AICMM

[ZeroAir]

AICMM, thanks for the reply. Did you try doing that union without the glue?

[AICMM]

AeroAir,

When I do press fits (not to often anymore) I always use glue. You might also consider other types such as Restek's or Gerstel's view type unions. These use ferrules to maintain pressure on the press seal.

Best regards,

AICMM