Chromatography Forum

We are injecting 1-2ul water on a DB-624 column 75mx.53mmx3.0um for polars (acetaldehyde, methanol,nmp,acetone phenol etc etc) and are using this guard column:
Restek 10047 10mx.53mm Intermediate-Polarity Deactivated Guard/Retention Gap Columns/Transfer Lines (fused silica)
Has anyone used this guard column or have other suggestions that might work better?
Restek Cat.# 10084 10mx.53mm
Hydroguard Water-Resistant Guard/Retention Gap Columns/Transfer Lines (fused silica)
We are measuring anywhere from .5 to 1000 ug/mL and sometimes to MDL ~.05 ug/mL so are trying to improve our chromatography and reporting limits.
Agilent 6890 FID, splitless mostly and split @5:1,..we have several different methods depending on the analytes and concentrations, and yes I know the liner is not supposed to work with 2ul water but it does...
Thanks
E

Water injections in GC are tricky due to the thermal expansion of water. 2ul is way to much. When I did aqueous injections I used 0.5ul and my injection port at 120c. If you feel you must use 1-2ul, you may consider doing a pressure pulsed injection. This should limit the expansion of the water.
As for the Hydroguard coating I use steel hydroguard tubing for my transfer line connecting my P&T to the GC. Had no problems with it.

Water injections in GC are tricky due to the thermal expansion of water. 2ul is way to much. When I did aqueous injections I used 0.5ul and my injection port at 120c. If you feel you must use 1-2ul, you may consider doing a pressure pulsed injection. This should limit the expansion of the water.
As for the Hydroguard coating I use steel hydroguard tubing for my transfer line connecting my P&T to the GC. Had no problems with it.

I will second the Restek Hydroguard guard column, I have never had any problems using it so far. As Bigbear does, I use it mostly as heated transfer lines for purge and trap, but it should work well for aqueous injections, that is what it was designed for.

ok thanks appreciate the replies!