Bonded stationary phases silane, functional group

The stationary phase (sorbent) is the most important part of an SPE cartridge. The most common SPE phases are bonded silica-based materials. Various silanes are used to attach functional groups to the accessible areas of the silica particle. The functional group determines the identity and chromatographic characteristics of the phase. In addition, several nonsilica-based phases are also available. Samples that are dirty, complex, or highly concentrated will require larger amounts of phase for sufficient sample cleanup. 

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