Cation Exchange Resins | Thermo Fisher Scientific

Powerful solutions for downstream capture and polishing application

Cation exchange chromatography is a form of ion exchange chromatography in which a positively charged biomolecule binds to a negatively charged resin.

POROS resins for cation exchange

POROS CEX resins are designed for high dynamic binding capacity over a range of pH and conductivity conditions, thereby increasing process development flexibility and manufacturing throughput. The particle size enables outstanding resolution for superb impurity clearance independent of scale and flow rate. These 50 μm polymeric ion exchange chromatography resins can be used for the chromatographic separation of biomolecules, including recombinant proteins, monoclonal antibodies, DNA, viruses, and peptides. The resin backbone consists of crosslinked, rigid poly(styrene divinylbenzene). A polyhydroxyl surface coating allows low nonspecific binding, and surface functionalization with sulfopropyl yields a strong cation exchanger ionizable with pH 1–14.

POROS 50 μm HS and XS resins are strong cation exchange resins based on a sulfopropyl functionalization, designed for the purification of more basic proteins and biomolecules. They are especially well suited for the separation of process impurities and aggregates and are excellent choices for both capture and polishing applications. Both resins are designed for superior resolution; POROS XS facilitates higher dynamic binding capacity at increased salt concentrations.

POROS cation exchange applications:

• Bind/elute: Polish of many biomolecules such as mAbs, VLPs/viruses, fusion proteins, high pI recombinant proteins

• Flow through: Polish for mAbs by binding impurities under normal B/E conditions: impurity removal (aggregates, HCP, DNA, viruses)

Resin	POROS HS	POROS XS
Type of CEX resin	Strong	Strong
Surface chemistry	Sulfopropyl	Sulfopropyl
IgG binding capacity (mg/mL)	70	120
pH range	1–14	1–14
Pore size (Angstrom)	1,020	1,100

Binding capacity of POROS XS vs salt concentration and pH

Figure 1. Binding capacity of POROS XS resin with IgG at 5% breakthrough. High binding capacity is obtained under a wide range of process conditions. Column: 0.46 cm (D) x 20 cm (L); buffer: 20 mM MES; load: 5 mg/mL IgG; flow rate: 300 cm/hr.

Chromatogram showing high resolution properties of POROS XS and HS

Figure 2. POROS XS and HS resins present with similar, high-resolution properties. Column: 1 cm (D) x 20 cm (L); buffer A: 20 mM MES, 25 mM NaCl pH 6.2, buffer B: 20 mM MES, 1 M NaCl pH 6.2; elution: gradient 10%–50% buffer B, 7.5 CV; flow rate: 300 cm/hr; protein mix: chymotrypsinogen A, cytochrome C, and lysozyme.