silica deactivation

[Najat]

I need to use silica gel to clean up my sample for the analysis of a group of flame retardants ranging from slightly polar to extremely non polar. I check some methods, some deactivate silica and some didn't deactivate. My question, do I need to deactivate the silica?

[krickos]

Hi

In my limited experiance I can at least say that it sometimes dependends on the flame retardant, for instance deca-BDE (BDE-209) it is known to stick to silanols during sample clean up and analysis (less inert GC columns cause degradation). While like hexa-BDE seems less sensitive.