deactivated from acid/base? how to

[pochengjean]

I frequently see the DB columns, DA columns, and deactivated glass insert.

How do they deactivated those components?

[tom jupille]

deactivated glass (also referred to as "silanized" is treated with something like trimethylchlorosilane in order to make it less adsorptive (TMCS reacts with silanols).

"DB" and "DA" for HPLC packings are more vague terms (meaning "deactivated for bases" and "deactivated for acids"). The actual treatment varies tremendously from manufacturer to manufacturer.

[pochengjean]

so, the column is treated to be deactivated for base/acid during the packing process?

[tom jupille]

No, it usually refers to treating the silica gel before the bonded phase is attached. May sometimes involve additional treatment after bonding, but before packing.