Covalent sorbents have either epoxy, aldehyde, isocyanate or thiopropyl functional groups that are bound to the silica backbone by a hydrocarbon chain. These groups will react selectively with analyte functional groups causing a formal bond between the stationary support and the analyte.
In the case of the aldehyde sorbent, an analyte with a primary amine performs a nucleophilic attack on the aldehyde functionality in the sorbent. This attack results in a Schiff base, with the amine immobilized on the stationary support. This chemistry can be utilized to bind proteins, such as antibodies, to the support, allowing highly specific extractions.
The thiopropyl functional group scavenges for alkylating agents, alcohols and amines.
Thiopropyl is the only stock product available, contact UCT for other covalent chemistry availabilities.