I'm no expert on the subject, but this afternoon kssabnis uploaded a new abbreviated App Note that looks like it's related: Analysis of Distilled Spirits Using an Agilent J&W DB-WAX Ultra Inert Capillary GC Column. A couple week ago, there was another one: Lavender Oil Analysis Using Agilent J&W DB-WAX Ultra Inert Capillary GC Columns.
Can you please describe what sort of sample you are analyzing? That ought to help us figure out what sort of chemistry may be going on, and thus what kind of column may be appropriate.
kgl, do you have any guidance regarding different inert and ultra inert columns?
Thanks. - Josh
As Josh mentioned, you can try our new DB-WAX Ultra inert GC columns. DB-WAX UI GC columns can deliver excellent inertness with more reliable peak shape and better longevity performance than many popular WAX columns including ZB-WAX plus. More detailed information, please see application note 5991-6683EN "A New PEG GC Column with Improved Inertness Reliability and Column Lifetime" and 5991-6709EN "DB-WAX UI columns brochure".
Thanks for the information, ella!
For the reader, here are links to those items:
Our colleague the kssabnis just created a new abbreviated document in Application Notes: GC and GC/MS corresponding to that app note (actually a technical overview): A New PEG GC Column with Improved Inertness Reliability and Column Lifetime -Agilent J&W DB-WAX Ultra Inert Polyethylene Glycol Column.
By having this document in the community, any member may comment on it and perhaps have a conversation with the authors.
Enjoy! - Josh
Reading through the app note (A New PEG GC Column with Improved Inertness Reliability and Column Lifetime), I found that Figure 6 should be particularly helpful to you, showing a side-by-side comparison of the ZB-WAXplus and DB-WAX UI. It sure looks like the UI will help with your degradation problem.
akv is one of the authors on that App Note. Allen, do you have any additional insights?
Thanks. - Josh
Thanks for the replies.
I will look into the Agilent UI WAX column (and a few similar options from other suppliers).
The analyte is primarily thermally degraded - so I have got a good peak but by using a low injector temperature (120C), 35C initial oven (6890 GC with small fan - so cannot really go lower), 2C ramp to 250C, and high He flow 3mL/min (constant flow). Splitless injection (splits of 10:1 or 20:1 did not help).
Column is ZB-WAX 30m * .250 * .25.
This is very slow - but works.
I think I will buy a more inert column - with thicker phase , and slightly wider bore, and shorter length.
Thanks again for all your opinions.
think about your thermal degradation. This normally happens already in the liner, even at lower temperatures. I would recommend to use an Ultra-Inert liner too, if you cannot do cold-on-column injections.
Thermal degradation that happens on the column, shows up as a kind of fronting on peaks. Smaller fragments from the degradation process elute faster than the bigger parent molecule, not as tailing.