Chromatographic resins with high capacities and selectivities differing from those seen with traditional hydrophobic interaction and ion exchange media are now in demand. Mixed-mode chromatography media is an alternative. Some mixed-mode resins combine both traditional hydrophobic interaction and ion exchange media. This poster introduces TOYOPEARL® MX-Trp-650M, a high-capacity weak cation mixed-mode resin for the purification of biomolecules.

The polymethacrylic base bead was chemically modified with the amino acid tryptophan which combines a weak cationic group with a hydrophobic functional group. The resulting resin exhibited high dynamic binding capacities (approximately 90 mg/mL for IgG). Separation of proteins from crude feedstocks with measured conductivities of 12 mS/cm was routinely possible. Increasing the salt concentration up to 200 mmol/L NaCl at pH values as low as 4.0 also had capacities usable in large scale biomolecule purifications.

Experiments were performed to compare TOYOPEARL MX-Trp-650M selectivity with two commercially available cation exchange resins and a commercially available mixed-mode resin. The selectivity was demonstrated by the elution of three common proteins at different pH values. Overall, TOYOPEARL MX-Trp-650M selectivity was different from the cation exchange media as well as the other commercially available mixed-mode resin.