One thing I get a nasty feeling about, is when statements are made about maximum temperatures of fused silica columns exceeding 400C without a clear indication of time. The max. temp. of a GC-column is a function of stationary phase stability and stability of the capillary tubing: this is always time-related.
There are several stabilized stationary phases that can be used at very high temperatures, like Rxi-5HT. Such phases are stable up to high temperatures but when fused silica columns are heated for 2 days at 430C, the outside polyimide coating will be damaged, providing risk for column breakage, (and a vacuum cleaner to clean your GC..). I do not understand anybody can justify to say that “their” polyimide fused silica columns can be used up to 430C..
The only way to exceed the 400C limit succesfully is to use metal-clad or full-metal columns, like Restek’s MXT line. You will be surprised to see how inert these columns are. They can compete with fused silica..
