By ad on Thursday, June 26, 2003 - 03:19 am:
we had a litle discusion in our lab. we are developing a new method with an HILIC-column(waters atlantis). for som reasen someone sugested using higher temperature (60 °C). someone else said this was not an good idea becouse the HILIC-column would get a realy short life-time becouse of desoling of silica at higher temp. my idea was that we use an pre-column and this pre-column would act as an satarusation-column. the elluent would be saturated with silica before entering the annalitical column and no silica of the annalytical column wil desolve at higher temp. so only the lifetime of the (cheap) pre-column will be affected.
doe anybody have anything to add to this discusion?
thanks for all input.
By Tim on Thursday, June 26, 2003 - 03:34 am:
Why do they want to use a higher temperature - have you tried it at a lower temperature (say 30-40°C)?
By ad on Thursday, June 26, 2003 - 07:35 am:
ok, there was a problem that could be solved by raising the tamperature. now the question is, is it a robust solution.
we can try it, but if sombody kwons that it will never be a robust solution, we can save the trouble....
By Anonymous on Thursday, June 26, 2003 - 08:30 am:
ad,
A saturator column will help but there will still be a very limited lifetime of the analytical column at higher temps.
Regards,
Mark
By Uwe Neue on Thursday, June 26, 2003 - 03:31 pm:
I think that a saturation column will do just fine. It has been a good solution for the stabilization of silica columns in many cases. Go and try it.
By HW Mueller on Thursday, June 26, 2003 - 11:29 pm:
In order for a saturation column to work the involved reactions have to be reversible (an equilibrium must be posible). I just wonder whether it is known which of the chemistries of columns are reversible? (For instance, is the detachment of a C-18 reversible?)
By Einar Pontén - SeQuant AB on Friday, June 27, 2003 - 05:58 am:
Use a ZIC™-HILIC column instead! The silica support is shielded by the hydrophilic zwitterionic phase and it is stable. Why making things complicated?
Recirculating a silica saturated mobile phase does not seem nice in practice. Although, it is often mentioned in textbooks. In fact, I do beleive that Uwe Neue previously (on these pages) has been quite negative to that approach.
By Anonymous on Thursday, July 17, 2003 - 04:10 am:
At low pH, this column should last. Try it and post back to us and let us know.
If I am not mistaken, the ZIC-HILIC column is also silica-based and would suffer from potentially shorter lifetimes at high temp. The short chained ligand would not provide that much protection as compared to a C18 ligand.
As always, choices and tradeoffs must be made.