The packing of C8/SCX and C8/SAX mixed-mode SPE cartridges is a bonded mixed phase of C8 and SCX or SAX, showing dual properties in the adsorption of neutral, acidic, basic, and zwitterionic compounds.
This type of mixed-mode ion-exchange cartridge is ideal for purifying charged or neutral sexual compounds such as drugs and metabolites in biological fluids.
C8/SAX SPE Cartridge
The functional group of C8/SAX consists of proportionally bonded octyl and quaternary amino groups with dual retention: the octyl group provides moderate hydrophobic interaction and the quaternary amino group provides strong anion exchange interaction.
The C8/SCX mixed-mode SPE cartridge is composed of a C8 alkyl stationary phase and a silica-based strong cation exchange stationary phase SCX in an optimized ratio, which provides a dual retention mechanism. C8 interacts with the hydrophobic portion of the analyte, while SCX interacts with the protonated amino portion of the analyte.
Due to the strong dual interaction between the sorbent and the analyte, stronger wash solvents and wash conditions are allowed to remove the interferents adsorbed on the sorbent.
Detection of Drugs and Metabolites in Biological Fluids; Detecting Drug Abuse.