Question

Why are gas chromatographic stationary phases often bonded and cross-linked? What do these

terms mean?

Short answer

Bonded and cross-linked, these terms are explained as follows: Bonding is a process that occurs between monomolecular layer with silica's of the stationary phase and involves chemical reaction.Cross linking is the process carried out after the column is coated with polymer and it's carried in situ.Those are performed to preserve stationary phase.

Step-by-step solution

Bonding.

Bonding is a process that occurs between monomolecular layer with silica's of the stationary phase and involves chemical reaction.

Cross linking.

Cross linking is the process carried out after the column is coated with polymer and it's carried in situ.Those are performed because columns that are untreated might bleed which means they are losing their stationary phase during the elution process (part that's not immobilized in small amounts). Also, cross-linked and bonded columns might be backflushed to remove unnecessary species or contaminants without loss of the stationary phase, especially significant loss.