Thermo Scientific™ POROS™ XS Strong Kation Exchange Resin

A major improvement on traditional cation exchangers, POROS XS resin sets the standard for cation exchange chromatography.

• Dynamic binding capacity leads to reduced column size, smaller footprint, decreased buffer usage, and reduced cycling
• High resolution supports better product yield and improved impurity clearance
• Robust salt tolerance allows improved process flexibility, alignment, and process flow streamlining
• Low back pressure and linear pressure responses help improve scalability
• Rigid polymeric bead with covalent surface chemistry makes for easier handling and packing, and superior physical and chemical stability, resulting in a robust manufacturing process

Dynamic Binding Capacity

POROS XS resin has a high binding capacity of more than 100 mg/mL, at 5% breakthrough, over a broad range of process conditions. Figure 1 demonstrates unparalleled binding capacity across a broad range of pH and salt conditions. Higher dynamic binding capacity was achieved by optimizing the base bead pore structure and surface chemistry.

High Resolution

Using an optimized 50 μm particle size, POROS XS resin maintains the superior resolving capacity of POROS HS resin (Figure 2) while overcoming the challenging impurity levels associated with high titer processes. Resolution is consistent across a wide range of operating flow rates (Figure 3) and maintained independent of protein load (Figure 4).

Robust Salt Tolerance

POROS XS resin has high and consistent protein capacity across a broad range of salt concentrations (Figure 5) up to 150 mM NaCl (15 mS/cm conductivity). The ability to load columns under higher conductivity reduces or helps eliminate the dilution of column feed streams or the removal of unit operations, such as tangential flow filtration. The optimized surface ionic capacity of POROS XS resin minimizes competitive binding between the protein of interest and the counterion, resulting in superior salt tolerance.